Merge pull request '[READY][Gameplay] #310 Host transition idempotency and error catalog for scoreboard -> next round / finish' (#320) from dev/issue-310-host-transition-idempotency-v2 into main

Reviewed-on: #320
Reviewed-by: reviewer-bot <review-no-reply@weircon.dk>

.claude/settings.json

@@ -0,0 +1,7 @@
+{
+  "permissions": {
+    "allow": [
+      "Bash"
+    ]
+  }
+}

.gitea/workflows/ci.yml

@@ -31,3 +31,17 @@ jobs:
 
       - name: Tests
         run: python manage.py test lobby -v 1
+
+      - name: Setup Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: "22"
+
+      - name: Install SPA dependencies
+        run: |
+          npm ci --prefix frontend/angular
+          node -e "require('./frontend/angular/node_modules/rollup/dist/native.js')" \
+            || npm install --prefix frontend/angular
+
+      - name: SPA Angular smoke tests
+        run: npm --prefix frontend/angular test

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Changelog
 
+## [Unreleased]
+### Docs
+- Added `docs/ISSUE-279-I18N-MVP-CLOSEOUT.md` with the issue #279 i18n MVP close-out note, including migration impact, reusable release-note text, and a release-readiness checklist refreshed against `main@1bc4c27` after PR #282/#283 landed on 2026-03-13 UTC.
+- Clarified that the close-out note supersedes earlier PR snapshot assumptions and now treats PR #282 (`6ad5430`) and PR #283 (`1bc4c27`) as already merged on `main`.
+
 ## [0.1.0] - 2026-02-27
 ### Added
 - Projekt scaffold for Weirsøe Party Protocol (Django 6.0.2)

CLAUDE.md

@@ -0,0 +1,119 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+**Weirsøe Party Protocol** is a Danish party game web platform (Jackbox-style) where games display on a primary screen and players participate via mobile. The MVP game is "Fup og Fakta" (a Fibbage-style lie-and-guess game).
+
+- Backend: Django 6.0.2 + Django Channels (WebSockets) + Redis
+- Frontend: Angular 19 shell + shared TypeScript API client library
+- Database: MySQL (SQLite fallback for dev)
+- Deployment: Proxmox LXC containers (not Docker)
+
+## Commands
+
+### Backend (Django)
+```bash
+python manage.py runserver       # Dev server
+python manage.py migrate         # Apply migrations
+python manage.py test            # Run all backend tests
+python manage.py test lobby      # Run tests for a single app
+python manage.py shell           # Django shell
+```
+
+### Frontend — API client (`/frontend`)
+```bash
+cd frontend
+npm install
+npm test       # Vitest unit tests
+npm run build  # TypeScript compile check (--noEmit)
+```
+
+### Frontend — Angular shell (`/frontend/angular`)
+```bash
+cd frontend/angular
+npm install
+npm start      # Dev server (ng serve)
+npm run build  # Production build
+npm run test   # Vitest unit tests
+```
+
+### i18n validation
+```bash
+python scripts/check_i18n_drift.py   # Check for key drift between locales
+```
+
+## Architecture
+
+### Backend apps
+
+| App | Purpose |
+|-----|---------|
+| `partyhub/` | Main Django project — settings, root URLs, ASGI/WSGI, i18n bootstrap |
+| `lobby/` | Session & player management — create/join session, locale-aware error responses |
+| `fupogfakta/` | Game logic — all domain models, score calculation (server-authoritative) |
+| `realtime/` | WebSocket event layer (stub) |
+| `voice/` | Voice/TTS interface (stub, Phase 2) |
+| `core_admin/` | Health endpoint (`/healthz`), global admin |
+
+**Key domain models** (all in `fupogfakta/models.py`): `GameSession`, `Player`, `Category`, `Question`, `RoundConfig`, `RoundQuestion`, `LieAnswer`, `Guess`, `ScoreEvent`.
+
+Score calculation is server-side only. `ScoreEvent` provides an auditable trail of all point changes.
+
+### Frontend layers
+
+1. **Shared API client** (`frontend/src/`) — pure TypeScript, framework-agnostic. Defines all API types (`api/types.ts`) and HTTP client abstraction (`api/client.ts`).
+2. **Angular shell** (`frontend/angular/`) — Angular 19 standalone components (no NgModules), hash-based routing. `host-shell.component` for the presenter screen; `player-shell.component` for mobile players.
+
+The Angular shell consumes the shared client via `frontend/src/api/angular-client.ts`.
+
+### Real-time flow
+
+`LOBBY → LIE → GUESS → REVEAL → FINISHED` — phase transitions broadcast a `PhaseViewModel` to all connected clients via WebSocket. Clients are read-only; only the server is authoritative for state.
+
+### i18n
+
+- **Single source of truth**: `shared/i18n/lobby.json` (keys in both `en` and `da`)
+- Loaded once at startup with LRU cache (`partyhub/i18n_bootstrap.py`)
+- Key naming: domain-first — `frontend.ui.host.*`, `frontend.ui.player.*`, `backend.errors.*`, `backend.error_codes.*`
+- Locale resolved from `Accept-Language` header; missing key returns key + logs warning; missing translation falls back to `en`
+
+## Key Conventions
+
+### Errors
+Backend error responses use stable machine-readable codes (`backend.error_codes.*`) with separately localized messages. Never couple error code strings to locale.
+
+### Game constraints (MVP)
+- 3–12 players per session
+- Session codes: 6-char alphanumeric (no 0/O/1/I/L)
+- Anti-cheat: no duplicate lies, lies cannot match the correct answer, answer order randomized
+
+### Git workflow
+- `main`: stable baseline
+- `feature/<name>`: development branches
+- `release/vX.Y.Z`: release preparation
+- Release: merge → create release branch → update `VERSION` + `CHANGELOG.md` → tag → push
+
+### TypeScript
+Strict mode required. Target ES2022. API response interfaces in `frontend/src/api/types.ts` must match backend responses exactly.
+
+### Database
+Use `ForeignKey` with explicit `on_delete` (`PROTECT`/`CASCADE`/`SET_NULL`). Add `db_index=True` on frequently queried fields. Migrations are auto-generated by Django and versioned in `migrations/`.
+
+## Environment Variables
+
+```
+DJANGO_SECRET_KEY, DJANGO_DEBUG, DJANGO_ALLOWED_HOSTS
+DB_ENGINE, DB_NAME, DB_USER, DB_PASSWORD, DB_HOST, DB_PORT
+CHANNEL_REDIS_HOST, CHANNEL_REDIS_PORT
+USE_SPA_UI (fallback: WPP_SPA_ENABLED)
+WPP_SPA_ASSET_BASE, WPP_SPA_ASSET_VERSION
+```
+
+## Test Files of Note
+
+- `lobby/tests.py` — comprehensive Django TestCase coverage for session/player/i18n/error flows
+- `frontend/angular/src/app/api-contract-smoke.spec.ts` — API contract smoke tests
+- `frontend/angular/src/app/lobby-i18n.spec.ts` — i18n parity checks
+- `frontend/tests/lobby-loader.parity.test.ts` — shared i18n loader parity

PROMPT.md

@@ -0,0 +1,71 @@
+# Ralph Loop: Implement WebSocket push for Weirsøe Party Protocol
+
+## Context
+- Project: /home/agw/projects/weirsoe-party-protocol
+- Backend: Django 6.0.2 + Django Channels + Redis
+- The full game REST flow is already implemented in lobby/views.py
+  (create_session, join_session, start_round, show_question, submit_lie,
+  mix_answers, submit_guess, calculate_scores, reveal_scoreboard, finish_game)
+- realtime/ app exists but is a stub (no consumers.py, no routing)
+- partyhub/settings.py has channels in INSTALLED_APPS but no CHANNEL_LAYERS or routing
+- PO hard requirement: WebSocket push is mandatory in MVP (no polling)
+
+## What to build
+
+### 1. realtime/consumers.py — GameConsumer
+- AsyncJsonWebsocketConsumer
+- Connects to group game_{session_code} on connect (session_code from URL)
+- Player auth: session_token query param validated against Player model
+- Host auth: query param role=host, no token required for MVP
+- On disconnect: clean leave from group
+- Handles incoming message type "ping" -> replies with {"type": "pong"}
+- Forwards broadcast group events to WebSocket client
+
+### 2. partyhub/settings.py — CHANNEL_LAYERS
+Add CHANNEL_LAYERS using channels_redis.core.RedisChannelLayer.
+Read CHANNEL_REDIS_HOST (default 127.0.0.1) and CHANNEL_REDIS_PORT (default 6379) from env.
+
+### 3. partyhub/asgi.py — ASGI routing
+Wire URLRouter so ws/game/<session_code>/ routes to GameConsumer.
+Keep existing HTTP routing intact.
+
+### 4. realtime/routing.py
+Define websocket_urlpatterns list.
+
+### 5. realtime/broadcast.py — broadcast helper
+- async def broadcast_phase_event(session_code, event_type, payload)
+  Sends to group game_{session_code} via channel layer.
+- def sync_broadcast_phase_event(session_code, event_type, payload)
+  Sync wrapper using async_to_sync for calling from sync REST views.
+
+### 6. lobby/views.py — hook broadcasts into phase transitions
+After each phase transition, call sync_broadcast_phase_event:
+- start_round      -> phase.lie_started   (question prompt + time limit)
+- show_question    -> phase.question_shown (question text)
+- mix_answers      -> phase.guess_started  (shuffled answers + time limit)
+- calculate_scores -> phase.scores_calculated (per-player score delta)
+- reveal_scoreboard -> phase.scoreboard   (ranked player list)
+- finish_game      -> phase.game_over     (final rankings)
+
+### 7. realtime/tests.py — basic tests
+- Connect/disconnect test using channels.testing.WebsocketCommunicator
+- Verify a broadcast reaches a connected client
+
+## Constraints
+- Keep auth simple: session_token query param for players, unauthenticated host in MVP
+- Use async_to_sync wrapper for sync REST views calling async broadcast
+- Do not break existing REST tests (python manage.py test lobby must still pass)
+- After each file written, run: python manage.py check
+- Follow existing code style in lobby/views.py
+
+## Completion criteria
+Output the exact text: WEBSOCKET COMPLETE
+
+...when ALL of the following are true:
+- realtime/consumers.py exists and handles connect/disconnect/ping
+- realtime/broadcast.py exists with sync_broadcast_phase_event
+- partyhub/settings.py has CHANNEL_LAYERS configured
+- partyhub/asgi.py routes ws/game/<code>/ to GameConsumer
+- All 6 phase transitions in lobby/views.py call sync_broadcast_phase_event
+- python manage.py check passes with no errors
+- python manage.py test lobby passes (existing tests not broken)

TODO.md

@@ -37,8 +37,8 @@ Byg **Weirsøe Party Protocol**: en dansk party-webapp platform ala Jackbox, hvo
   - [x] `core_admin` (global administration)
   - [x] `fupogfakta` (Spil 1)
   - [x] `lobby` (room/session/player join flow)
-  - [x] `realtime` (channels events, game state broadcast)
-  - [x] `voice` (fælles voice-acting interface)
+  - [x] `realtime` (app-skelet oprettet — consumers/routing IKKE implementeret endnu)
+  - [x] `voice` (fælles voice-acting interface — stub)
 - [x] Miljøfiler (`.env.test`, `.env.prod` skabeloner)
 - [x] Konfig for MySQL test/prod
 
@@ -53,14 +53,15 @@ Byg **Weirsøe Party Protocol**: en dansk party-webapp platform ala Jackbox, hvo
 - [x] `ScoreEvent` (auditérbar pointslog)
 
 ### Fase 3 — Spilflow `Fup og Fakta`
-- [x] Lobby: host opretter session, spillere joiner via kode
-- [x] Runde starter med kategori
-- [x] Spørgsmål vises -> alle skriver løgn inden X sek
-- [x] System blander korrekt svar + løgne
-- [x] Guessfase: alle gætter inden Z sek
-- [x] Pointudregning (konfigurerbar pr. runde)
-- [x] Scoreboard + næste spørgsmål/runde
-- [x] Slutresultat
+- [x] Lobby: host opretter session, spillere joiner via kode (REST)
+- [x] Runde starter med kategori (REST)
+- [x] Spørgsmål vises -> alle skriver løgn inden X sek (REST)
+- [x] System blander korrekt svar + løgne (persisted i JSONField, anti-cheat dedup)
+- [x] Guessfase: alle gætter inden Z sek (REST)
+- [x] Pointudregning (konfigurerbar pr. runde, ScoreEvent audit trail)
+- [x] Scoreboard + næste spørgsmål/runde (REST)
+- [x] Slutresultat (REST)
+- [x] **WebSocket push af phase-events til host + spillere** (GameConsumer + broadcast.py, InMemoryChannelLayer i tests)
 
 ### Fase 4 — Voice-acting (platformkrav)
 - [ ] Definér TTS provider-interface
@@ -103,10 +104,11 @@ Byg **Weirsøe Party Protocol**: en dansk party-webapp platform ala Jackbox, hvo
 - [ ] Migrations + static + health checks
 
 ### Backlog — Need-to-have / Nice-to-have
-- [ ] (Need-to-have) Persistér mixed svarrækkefølge pr. round question, så alle spillere ser samme rækkefølge ved reconnect/refresh
+- [x] (Need-to-have) Persistér mixed svarrækkefølge pr. round question — DONE (JSONField + migration 0003 + test)
 - [x] (Need-to-have) Tilføj spiller-auth/session-token for submit_lie (pt. baseret på player_id i payload)
 - [ ] (Nice-to-have) Endpoint til status/progress i løgnfasen (antal indsendt ud af total)
-- [ ] (Need-to-have) [Fejltype: CI/lint F401] [Fil/område: core_admin/*, fupogfakta/tests.py+views.py, lobby/admin.py+models.py, realtime/*, voice/*] [Branch/PR: feature/f3-lobby-create-join, feature/fase0-mvp-fup-og-fakta, feature/lobby-mvp (ingen åbne PRs fundet)] Fjern ubrugte scaffold-imports (eller kør ruff check --fix) så quality gate kan blive grøn før merge.
+- [ ] (Need-to-have) Fjern ubrugte scaffold-imports i core_admin/*, realtime/*, voice/*, fupogfakta/views.py (kør `ruff check --fix`) så CI quality gate er grøn
+- [x] (Need-to-have) [Issue #251] Release-often lane: SPA MVP opdelt i 3 merge-klare micro-PR batches (plan + acceptance criteria dokumenteret i `docs/ISSUE-251-RELEASE-OFTEN-SPA-MVP-BATCH-PLAN.md`).
 - [ ] (Need-to-have) Rate limiting på join/submit endpoints
 - [ ] (Need-to-have) Session-kode brute-force beskyttelse
 - [ ] (Need-to-have) Audit-log for host-handlinger (start/stop/skip)

docs/I18N_ARCHITECTURE.md

@@ -0,0 +1,49 @@
+# Shared i18n architecture (frontend + backend)
+
+## Scope
+Issue #175 requires one shared i18n contract for MVP host/player flows across frontend and backend.
+
+## Source of truth
+- Catalog: `shared/i18n/lobby.json`
+- Locales:
+  - supported: `en`, `da`
+  - default/fallback: `en`
+
+Django (`lobby/i18n.py`) reads directly from the catalog. Frontend runtimes are Angular-first and use a shared loader (`frontend/shared/i18n/lobby-loader.ts`) so Angular shell and SPA fallback consume the same keyspace + locale normalization.
+
+## Key naming convention
+- Domain-first namespaces:
+  - `frontend.ui.common.*`
+  - `frontend.ui.host.*`
+  - `frontend.ui.player.*`
+  - `frontend.errors.*`
+  - `backend.errors.*`
+  - `backend.error_codes.*`
+- UI lookup keys in Angular are shortened aliases mapped under `frontend.ui`, e.g.:
+  - `host.start_round`
+  - `player.submit_guess`
+  - `common.session_code`
+- Backend API errors return stable code + localized message:
+  - `error_code` = machine-stable key from `backend.error_codes`
+  - `error` = localized message from `backend.errors`
+  - `locale` = resolved request locale
+
+## Fallback model (robust)
+1. Resolve requested locale (`Accept-Language` on backend, user/browser preference on frontend).
+2. If locale unsupported -> use default `en`.
+3. If key missing -> return key and log warning.
+4. If locale translation missing for key -> fallback to `en` translation.
+
+## Audio-routing policy
+- Catalog capability: `frontend.capabilities.client_has_no_audio_output = true`
+- Host/player clients expose this as a read-only capability flag.
+- Policy: phone clients must not play audio directly; only primary/host output is allowed.
+
+## Verification
+- Backend tests: `lobby/tests.py` i18n coverage for locale selection + fallback + error-code/message matrix.
+- Frontend smoke/e2e-level unit coverage:
+  - `frontend/angular/src/app/lobby-i18n.spec.ts`
+  - `frontend/angular/src/app/i18n-mvp-flow-smoke.spec.ts`
+  - `frontend/angular/src/app/features/host/host-shell.component.spec.ts`
+  - `frontend/angular/src/app/features/player/player-shell.component.spec.ts`
+  - `frontend/tests/lobby-loader.parity.test.ts` (minimal da/en key parity guard for shared keyspace)

docs/ISSUE-175-I18N-SHARED-CONTRACT-ARTIFACT.md

@@ -0,0 +1,35 @@
+# ISSUE-175 Artifact — shared i18n contract + MVP host/player flow
+
+## Delivered
+- Shared i18n contract is centralized in `shared/i18n/lobby.json` (da/en, default `en`, robust fallback).
+- Frontend host/player MVP copy is read via shared keys (no hardcoded Danish strings in Angular MVP flow components).
+- Backend error messages resolve from shared keyspace with locale-aware API payload (`error_code`, `error`, `locale`).
+- Audio-routing policy is explicit and shared: `frontend.capabilities.client_has_no_audio_output=true`.
+- Architecture + key naming documented in `docs/I18N_ARCHITECTURE.md`.
+
+## Smoke / e2e evidence
+### Backend locale + fallback
+Command:
+```bash
+. .venv/bin/activate && python manage.py test \
+  lobby.tests.LobbyFlowTests.test_join_error_localizes_to_danish_with_accept_language_header \
+  lobby.tests.LobbyFlowTests.test_join_error_falls_back_to_english_for_unsupported_locale \
+  lobby.tests.I18nResolverTests
+```
+Result:
+- PASS (7 tests)
+- Confirms `da` localization and fallback to `en` for unsupported locale.
+
+### Frontend host/player + language switch + audio policy
+Command:
+```bash
+cd frontend/angular
+npm test -- --run \
+  src/app/lobby-i18n.spec.ts \
+  src/app/i18n-mvp-flow-smoke.spec.ts \
+  src/app/features/host/host-shell.component.spec.ts \
+  src/app/features/player/player-shell.component.spec.ts
+```
+Result:
+- PASS (22 tests)
+- Includes smoke for host/player copy in **both en and da** and verifies primary-only audio policy flag (`clientHasNoAudioOutput=true`).

docs/ISSUE-180-SPA-NEXT-ROUND-FINAL-LEADERBOARD-EVIDENCE.md

@@ -0,0 +1,28 @@
+# Issue #180 Evidence — SPA next-round + final leaderboard
+
+## Flow log (Angular SPA)
+1. Host reaches `reveal` phase and runs `loadScoreboard()` (`GET /lobby/sessions/:code/scoreboard`).
+2. Host can start next round directly in SPA via `startNextRound()` (`POST /lobby/sessions/:code/rounds/next`) and then session hydrate (`GET /lobby/sessions/:code`) without page reload.
+3. Host can finish game directly in SPA via `finishGame()` (`POST /lobby/sessions/:code/finish`), rendering winner + sorted final leaderboard (plus raw payload for debug) in the same shell.
+4. Player SPA renders final leaderboard from refreshed finished-session payload (sorted by score desc, nickname tiebreak) without leaving SPA route.
+5. Error/retry paths are implemented and covered:
+   - scoreboard failure -> `scoreboardError` + retry button
+   - next-round failure -> `nextRoundError` + retry button
+   - finish-game/final-leaderboard failure -> `finishError` + retry button
+
+## Test evidence
+### `frontend/angular` (Vitest)
+- `src/app/features/host/host-shell.component.spec.ts`
+  - `runs next-round transition without reload and clears scoreboard payload`
+  - `captures finish-game failure for retry and stores final leaderboard on success`
+- `src/app/features/player/player-shell.component.spec.ts`
+  - `builds final leaderboard in finished status without legacy page hop`
+
+Result:
+- Test Files: 2 passed
+- Tests: 9 passed
+
+### `frontend` shared SPA tests (regression)
+Result:
+- Test Files: 5 passed
+- Tests: 24 passed

docs/ISSUE-188-SPA-CUTOVER-HARDENING-ARTIFACT.md

@@ -0,0 +1,47 @@
+# Issue #188 Artifact — SPA cutover hardening (asset versioning + rollback)
+
+## Scope
+Acceptance for `[READY][SPA][P11] Cutover hardening`:
+1. Dokumenteret strategi for cache-busting/versionering af SPA assets i Django staticfiles/reverse proxy setup.
+2. Konfigurerbar rollback-procedure for `USE_SPA_UI` (trin-for-trin, target <10 min).
+3. Smoke-artefakt for både SPA on/off i samme release-vindue.
+4. Ingen gameplay-ændringer.
+
+## 1) Asset versioning/cache-busting strategi
+Implementeret i SPA shell render-path:
+
+- Konfiguration i `partyhub/settings.py`:
+  - `WPP_SPA_ASSET_BASE` (eksisterende)
+  - `WPP_SPA_ASSET_VERSION` (ny)
+- `lobby/ui_views.py` injicerer `spa_asset_version` til template-context.
+- `lobby/templates/lobby/spa_shell.html` appender `?v={{ spa_asset_version }}` på:
+  - `styles.css`
+  - `main.js`
+
+Effekt:
+- Ny release-version (fx SHA/tag) kan tvinge cache-miss i browser/proxy uden ændring af route.
+- Rollback kan pege på tidligere stabil version-token med samme mekanisme.
+
+## 2) Rollback playbook (`USE_SPA_UI`) — target <10 min
+Dokumenteret i `docs/spa-cutover-flag.md`:
+
+1. Sæt `USE_SPA_UI=false`.
+2. Sæt `WPP_SPA_ASSET_VERSION` til sidste stabile release-token.
+3. Deploy/reload app-processer.
+4. Verificér legacy routes (`/lobby/ui/host` + `/lobby/ui/player`).
+5. Kør hurtig smoke sanity.
+6. Log trigger/timestamp/resultat i smoke artifact.
+
+## 3) Smoke artifact for SPA OFF/ON i samme release-vindue
+Dokumenteret i:
+- `docs/UI_SMOKE.md` (sektion: "Samme release-vindue: SPA OFF + ON verifikation")
+- `docs/STAGING_GAMEPLAY_SMOKE_ARTIFACT.md` (template udvidet med release-window check + `WPP_SPA_ASSET_VERSION`)
+
+Krav:
+- OFF-pass (legacy) og ON-pass (SPA) køres i samme deploy/release-vindue.
+- Begge passes logges i samme artifact med UTC timestamps og version-token.
+
+## Non-goals bekræftet
+- Ingen gameplay-regler ændret.
+- Ingen API-kontrakter ændret.
+- Ingen UX-redesign; kun drift/cutover-hardening.

docs/ISSUE-200-SPA-HOST-PLAYER-PHASE-SYNC-ARTIFACT.md

@@ -0,0 +1,57 @@
+# Issue #200 Artifact — SPA host→player phase sync (no reload)
+
+## Scope
+Acceptance for `[READY][SPA][P14] Gameplay MVP-del 5`:
+1. Host handlinger (`start round` / `næste fase`) propagere korrekt til player-ruter i SPA.
+2. Happy-path artefakt for én fuld faseovergang uden page reload.
+3. Sync-fejl giver kontrolleret fallback/error state.
+
+Afgrænsning overholdt: ingen nye spilregler og ingen redesign af backend event-model.
+
+## Happy-path faseovergang (uden page reload)
+Reference-flow i Angular shell:
+
+1. **Host starter runde/fase**
+   - Host action kalder backend endpoint (`POST /lobby/sessions/:code/start` eller fase-endpoint)
+   - Host shell hydrerer session igen (`GET /lobby/sessions/:code`)
+   - Host route synkes via hash-rewrite i samme SPA shell:
+     - `#/host/<phase>/<CODE>`
+     - Implementeret i `HostShellComponent.syncRouteFromSession()`
+
+2. **Player modtager ny fase via state sync**
+   - Player shell kører periodisk session-refresh (3s), uden hard reload
+   - Når `session.status` ændrer sig, synkes hash-route i samme SPA shell:
+     - `#/player/<phase>/<CODE>`
+     - Implementeret i `PlayerShellComponent.syncRouteFromSession()`
+
+3. **Ingen page reload**
+   - Routing sker med `window.history.replaceState(...)`
+   - URL opdateres i eksisterende SPA instans (ingen template-hop, ingen full refresh)
+
+## Kontrolleret fallback ved sync-fejl
+Når player-sync fejler (netværk/fetch/session-refresh):
+
+- UI går i kontrolleret connection-state:
+  - `reconnecting` ved online netværksfejl
+  - `offline` når browser rapporterer offline
+- Fejl vises med retry/back-to-join handlinger
+- Reconnect forsøges igen via timer (`scheduleReconnect`) uden at crashe shell
+
+## Verifikation (tests)
+Kørt i `frontend/angular` med Vitest:
+
+- `src/app/features/host/host-shell.component.spec.ts`
+  - Verificerer host-faseflow og hash-route sync uden reload
+- `src/app/features/player/player-shell.component.spec.ts`
+  - Verificerer periodisk player state sync + hash-route sync
+  - Verificerer reconnect/offline fallback ved sync-fejl
+- `src/app/api-contract-smoke.spec.ts`
+- `src/app/session-route-context.spec.ts`
+
+Kommando:
+
+```bash
+npm test -- --reporter=dot
+```
+
+Resultat: **4/4 testfiler grønne, 22/22 tests bestået**.

docs/ISSUE-205-I18N-FOUNDATION.md

@@ -0,0 +1,36 @@
+# Issue #205 — Django i18n foundation (da/en)
+
+## Implemented acceptance checks
+
+- **Django i18n setup for `en` + `da` with `en` fallback**
+  - `LANGUAGE_CODE` set to `en`.
+  - `LANGUAGES = [('en', 'English'), ('da', 'Danish')]`.
+  - `LocaleMiddleware` enabled in middleware chain.
+- **Shared-key resolver/adapter (no ad hoc backend mapping)**
+  - Backend error responses now resolve from shared catalog keys in `shared/i18n/lobby.json`.
+  - `lobby.i18n.api_error()` accepts a shared key and resolves locale-specific text.
+- **Representative API flow documented with key/locale behavior**
+  - `POST /lobby/join` with empty code returns:
+    - `error_code: "session_code_required"`
+    - localized `error`
+    - resolved `locale`
+- **Missing key handling deterministic and loggable**
+  - `resolve_error_message()` returns key string when key/translation is missing.
+  - Warning is logged (`lobby.i18n` logger) for missing key/translation.
+
+## Example response behavior
+
+### Request
+`POST /lobby/join` with empty code and header `Accept-Language: da`
+
+### Response (400)
+
+```json
+{
+  "error": "Sessionskode er påkrævet",
+  "error_code": "session_code_required",
+  "locale": "da"
+}
+```
+
+If locale is unsupported (e.g. `fr`), response uses `locale: "en"` and English message.

docs/ISSUE-207-I18N-AUDIO-SMOKE-ARTIFACT.md

@@ -0,0 +1,35 @@
+# Issue #207 Artifact — da/en locale switch + audio routing (primary-only)
+
+## Scope
+Acceptance for `[READY][i18n][P19]`:
+1. Verify one MVP host+player flow in both `en` and `da` locale context.
+2. Verify controlled fallback to `en` when a locale key is missing.
+3. Verify audio-routing policy is primary-only (client/player has no audio output).
+
+No new feature behavior added — this is verification-only evidence.
+
+## Smoke/e2e evidence (Angular shell test run)
+Executed from `frontend/angular`:
+
+```bash
+npm test -- --reporter=dot src/app/lobby-i18n.spec.ts src/app/features/host/host-shell.component.spec.ts src/app/features/player/player-shell.component.spec.ts
+```
+
+Evidence covered by the run:
+- `lobby-i18n.spec.ts`
+  - subscriber locale switch updates (`en -> da -> en`)
+  - controlled fallback where `da` key is removed during test and `en` copy is returned
+  - `clientHasNoAudioOutput === true` (primary-only audio routing)
+- `host-shell.component.spec.ts`
+  - host actions and route sync in SPA (no reload)
+- `player-shell.component.spec.ts`
+  - player session refresh/sync path and retry behavior
+
+## Policy evidence
+- Shared catalog capability: `shared/i18n/lobby.json`
+  - `frontend.capabilities.client_has_no_audio_output = true`
+- Angular host/player shells bind this capability:
+  - `HostShellComponent.clientHasNoAudioOutput`
+  - `PlayerShellComponent.clientHasNoAudioOutput`
+
+Conclusion: locale switching works in `da`/`en`, fallback resolves to `en` when locale key is intentionally missing, and client audio remains disabled by policy (`primary-only`).

docs/ISSUE-223-PLAYER-AUDIO-GUARD-ARTIFACT.md

@@ -0,0 +1,20 @@
+# Issue #223 — Telefon-klient audio guard (artifact)
+
+## Scope leveret
+- Telefon-/player-klient installerer en eksplicit audio guard ved mount (`installSecondaryDeviceAudioGuard`).
+- Guard overskriver `HTMLMediaElement.prototype.play` til en no-op på secondary device (client policy: `client_has_no_audio_output=true`).
+- Guard fjernes igen ved unmount (`ngOnDestroy`) så øvrige flows/enheder ikke påvirkes.
+- Ingen audio-controls er eksponeret i player-shell UI.
+
+## Acceptance mapping
+1. **Telefon-klient trigger ikke audio playback i kerneflow**
+   - Verificeret af test: `player-shell.component.spec.ts` (`installs secondary-device audio guard while player shell is mounted`).
+2. **Primær enhed påvirkes ikke negativt**
+   - Guard er scoped til player-shell lifecycle og restore'r original `play` ved destroy.
+3. **Enkel test/verifikation dokumenteret**
+   - Dokumenteret her + testkørsel nedenfor.
+
+## Testkørsel
+- Kommando:
+  - `cd frontend/angular && npm test -- src/app/features/player/player-shell.component.spec.ts`
+- Resultat: bestået (inkl. audio-guard test).

docs/ISSUE-224-TRUNK-SEQUENCE-175.md

@@ -0,0 +1,55 @@
+# Issue #224 — Trunk-sekvens for #175 (A/B/C)
+
+Formål: gøre #175 scheduler-klar som tre små, uafhængige og mergeklare bidder.
+
+## Sekvens
+
+### A) Backend i18n baseline
+- Tracking issue: #225
+- Scope:
+  - Backend resolver til locale (da/en)
+  - Fallback til `en` ved unsupported locale
+  - Stabil fejlkontrakt i payload (`error_code`, `error`, `locale`)
+- Mergebarhed: Kan merges uden frontend-ændringer.
+- Acceptance:
+  - Backend tests dækker `da` + fallback `en`
+  - Kontraktfelter er stabile i response
+
+### B) Shared key-map + locale-kontrakt
+- Tracking issue: #226
+- Scope:
+  - Én shared key-map for lobby/kerneflow
+  - Locale-kontrakt (tilladte locales, default locale, fallback-regler)
+  - Dokumentation af naming + ownership
+- Mergebarhed: Kan merges uden host/player UI-migrering.
+- Acceptance:
+  - Shared kontrakt findes ét sted
+  - Begge sider kan importere den
+  - Docs opdateret med da/en eksempler
+
+### C) Angular host/player integration + hardcoded-text cleanup
+- Tracking issue: #227
+- Scope:
+  - Angular host/player kerneflow bruger shared keys
+  - Hardcoded tekster fjernes i aftalte kernekomponenter
+  - Sprogskift verificeres i kritiske states
+- Mergebarhed: Kan merges selvstændigt når frontend-tests er grønne.
+- Acceptance:
+  - Korrekt i18n-copy i da/en i kerneflow
+  - Ingen hardcoded kerneflow-tekster tilbage
+  - Frontend tests/smoke grønne
+
+## PR-grænser (per bid)
+- 1 PR pr. bid (A/B/C) mod `main`
+- Mål: ~200–300 net LOC per PR (ekskl. generated artefakter)
+- Undgå cross-layer scope creep
+- Review-tid <30 min
+
+## Overordnet acceptance for #224
+- A/B/C-sekvens er tydelig med links
+- Hver bid er mergebar isoleret
+- Scheduler kan assign’e direkte uden ekstra afklaring
+
+## Verification (docs-only)
+- Verificeret at dokumentet kun beskriver trunk-sekvensen for issue #224 og linker til #225/#226/#227.
+- Ingen runtime-kode ændret; der er derfor ikke kørt kode/tests i denne PR.

docs/ISSUE-225-BACKEND-I18N-BASELINE-ARTIFACT.md

@@ -0,0 +1,44 @@
+# ISSUE-225 Artifact — Backend i18n baseline (resolver + fallback)
+
+Issue: **#225** (`[MVP][READY] #175-A: Backend i18n baseline (resolver + fallback)`)
+
+## Scope verified
+
+- Backend locale resolver supports `da` + `en` and normalizes language tags.
+- Unsupported locale requests fall back to default locale (`en`).
+- Error payload contract is stable for API errors:
+  - `error_code`
+  - `error`
+  - `locale`
+
+## Implementation references
+
+- Locale resolution + fallback chain:
+  - `lobby/i18n.py`
+  - `resolve_locale()`
+  - `resolve_error_message()`
+  - `api_error()`
+- Shared locale contract source:
+  - `shared/i18n/lobby.json` (`locales.default=en`, supported includes `en`, `da`)
+
+## Acceptance checks run
+
+Command:
+
+```bash
+.venv/bin/python manage.py test \
+  lobby.tests.I18nResolverTests \
+  lobby.tests.LobbyFlowTests \
+  lobby.tests.StartRoundTests
+```
+
+Result (2026-03-02):
+
+- `Ran 28 tests in 24.781s — OK`
+- `System check identified no issues (0 silenced).`
+- Confirms resolver behavior for locale normalization + fallback and stable error payload fields across flow endpoints.
+
+## Notes
+
+- Existing merged follow-ups in `main` include Accept-Language parsing fixes for q-values and locale tag normalization.
+- This artifact documents the final baseline state and verification evidence for #225.

docs/ISSUE-226-SHARED-KEYMAP-LOCALE-CONTRACT.md

@@ -0,0 +1,30 @@
+# ISSUE-226 — Shared key-map + locale-kontrakt (backend/frontend)
+
+## Source of truth
+- Single shared artifact: `shared/i18n/lobby.json`
+- Ownership is documented under `contract.ownership` in the same artifact.
+
+## Locale contract
+Defined under `contract.locale`:
+- default locale: `en`
+- supported locales: `en`, `da`
+- fallback rule: use default locale when requested locale is unsupported or a key translation is missing.
+
+## Shared backend→frontend key-map
+Defined under `contract.backend_to_frontend_error_keys`.
+
+Examples:
+- `session_not_found -> session_not_found`
+- `session_not_joinable -> join_failed`
+- `round_start_invalid_phase -> start_round_failed`
+
+This allows backend error codes to remain stable while frontend copy keys stay UX-oriented.
+
+## da/en example values
+From `shared/i18n/lobby.json`:
+- `frontend.errors.session_code_required.en = "Session code is required."`
+- `frontend.errors.session_code_required.da = "Sessionskoden er påkrævet."`
+
+## Verification
+- Backend: `python manage.py test lobby.tests.I18nResolverTests`
+- Frontend: `npm test -- --run tests/lobby-i18n.contract.test.ts`

docs/ISSUE-250-PRIMARY-DEVICE-AUDIO-POLICY-ARTIFACT.md

@@ -0,0 +1,16 @@
+# Issue #250 Artifact — MVP guardrail (telefon-klient uden lydafspilning)
+
+## Scope
+Implementeret guardrail for `primary-device only` audio policy i SPA player-flow.
+
+## Acceptance mapping
+1. **Telefon-klient flow indeholder ingen audio-play init-path**
+   - Test: `player-shell.component.spec.ts` → `does not trigger original media play during player-shell init path`.
+2. **Primær enhed policy er dokumenteret og testbar**
+   - Policy i contract: `shared/i18n/lobby.json` → `frontend.capabilities.client_has_no_audio_output=true`.
+   - Testbar via eksisterende guard-tests + init-path test i player-shell specs.
+3. **Krav er refereret i SPA-plan/cutover-noter**
+   - Dokumenteret i `docs/spa-cutover-flag.md` under *MVP audio policy guardrail (telefon-klient)*.
+
+## UX/i18n note
+- Player shell viser advarselstekst via i18n key: `frontend.ui.player.audio_policy_notice`.

docs/ISSUE-251-RELEASE-OFTEN-SPA-MVP-BATCH-PLAN.md

@@ -0,0 +1,124 @@
+# Issue #251 — Release-often lane for SPA MVP (3 micro-PR batches)
+
+## Formål
+Bryde SPA MVP-arbejdet op i **3 merge-klare micro-PRs** med tydelige acceptance criteria,
+så vi kan levere værdi oftere, reducere review-risiko og holde `main` grøn.
+
+## Scope (issue-bound)
+Denne plan dækker kun planlægning/acceptance for den kommende SPA MVP-lane.
+Implementering af de konkrete features sker i efterfølgende PRs.
+
+## Hard acceptance criteria for issue #251
+- [x] Der findes en dokumenteret plan med præcis **3 batches**.
+- [x] Hver batch har:
+  - [x] mål og afgrænsning
+  - [x] konkrete leverancer (kodeområder)
+  - [x] test/checks før merge
+  - [x] rollback-note
+  - [x] "ikke med i denne batch" for at undgå scope creep
+- [x] Batch-rækkefølgen er dependencies-sikker (batch B bygger på batch A, batch C på batch B).
+- [x] Hver batch kan merges/releaseres uafhængigt uden at blokere drift på `main`.
+- [x] Planen linker til konkrete dev-opgaver for lane-kørsel.
+
+## Batch-plan (merge-klare micro-PRs)
+
+### Batch A — SPA shell + routing baseline
+**Mål:** Et stabilt SPA-skelet med route-struktur og guard-basics.
+
+**Leverancer (kodeområder)**
+- `frontend/angular/src/app/app.routes.ts` (host/player entry routes + fallback)
+- `frontend/angular/src/app/session-route-context.ts` (baseline route guards)
+- `frontend/angular/src/app/app.component.*` (shell-nav + route outlet wiring)
+- `lobby/templates/lobby/spa_shell.html` (kompatibel shell-entry ved SPA cutover)
+
+**Done-kriterier**
+- Host- og player-entry routes kan åbnes uden runtime-fejl i samme SPA-shell.
+- Route guards afviser ugyldige parametre deterministisk (ingen hard crash).
+- `USE_SPA_UI=false` fortsætter med legacy-flow uden regression.
+
+**Checks før merge**
+- `cd frontend/angular && npm test -- --run src/app/app.routes.spec.ts src/app/session-route-context.spec.ts`
+- `cd frontend/angular && npm run build`
+- Manual smoke: `/lobby/ui/host` + `/lobby/ui/player` (både `USE_SPA_UI=false` og `true`).
+
+**Rollback-note**
+- Sæt `USE_SPA_UI=false` og redeploy; verificér legacy routes svarer 200.
+
+**Ikke med i batch A**
+- Fuld gameplay-state synkronisering.
+- Audio/polish og i18n finpudsning ud over baseline wiring.
+
+---
+
+### Batch B — Session-state + host/player sync MVP
+**Mål:** Korrekt synkronisering af session-state mellem host og spillerklient.
+
+**Leverancer (kodeområder)**
+- `frontend/angular/src/app/features/host/host-shell.component.ts`
+- `frontend/angular/src/app/features/player/player-shell.component.ts`
+- `frontend/src/api/angular-client.ts` (MVP-kald for status/phase-overgange)
+
+**Done-kriterier**
+- Host handlinger (`start`, `show`, `mix`, `score`, `next`, `finish`) afspejles hos player uden side-reload.
+- Session-phase transitions er deterministiske i happy-path (`lobby -> question -> score -> next/finish`).
+- Guardrails reducerer race-condition regressions ved hurtige phase-skift.
+
+**Checks før merge**
+- `cd frontend/angular && npm test -- --run src/app/features/host/host-shell.component.spec.ts src/app/features/player/player-shell.component.spec.ts`
+- `cd frontend && npm test -- --run tests/angular-api-client.test.ts`
+- Manual smoke: host action -> player phase sync indenfor forventet latenstid.
+
+**Rollback-note**
+- Slå `USE_SPA_UI=false`, redeploy, og kør hurtig gameplay-smoke i legacy flow.
+
+**Ikke med i batch B**
+- Avanceret UX-polish/animation.
+- Udvidet observability udenfor MVP-kritiske logs.
+
+---
+
+### Batch C — Lobby/join/start minimal flow + release readiness
+**Mål:** Gøre SPA MVP release-klar med fokus på stabilitet og driftssikkerhed omkring det minimale flow.
+
+**Leverancer (kodeområder)**
+- `frontend/angular/src/app/i18n-mvp-flow-smoke.spec.ts` + relevante shell-tests
+- `docs/UI_SMOKE.md` + `docs/STAGING_GAMEPLAY_SMOKE_ARTIFACT.md`
+- `CHANGELOG.md` release-input for SPA MVP lane
+
+**Done-kriterier**
+- End-to-end minimal flow (`lobby -> join -> start`) er dokumenteret PASS i SPA.
+- Fejl-/empty-/loading states for flowets kritiske skærme er verificeret.
+- Driftsteam kan udføre cutover + rollback uden tvetydighed.
+
+**Checks før merge**
+- `cd frontend/angular && npm test -- --run src/app/i18n-mvp-flow-smoke.spec.ts`
+- `python manage.py test lobby.tests.LobbyFlowTests`
+- Opdateret staging-smoke artifact med UTC tidsstempler og gate-resultat.
+
+**Rollback-note**
+- Brug eksisterende playbook i `docs/spa-cutover-flag.md` (`USE_SPA_UI=false` + asset-version rollback).
+
+**Ikke med i batch C**
+- Post-MVP featureudvidelser.
+- Større refactors uden direkte release-værdi.
+
+## Rækkefølge og parallel-kørsel
+- **Dependency-rækkefølge:** A -> B -> C.
+- **Kan køres parallelt uden konflikt:**
+  - Test-/doc-forberedelse til C kan startes parallelt med B (ingen blokering af runtime-kode), men merges først efter B.
+  - Drift-smoke templates kan opdateres tidligt, så længe de ikke ændrer runtime-adfærd.
+- **Må ikke køre parallelt:**
+  - Runtime routing/guard ændringer i A og session-sync logik i B på samme filer uden feature-flag koordinering.
+
+## Konkret lane-opgavebinding (dev-opgaver)
+- Batch A PR: `feat/issue-251-batch-1-spa-shell-routing`
+- Batch B PR: `feat/issue-251-batch-2-session-sync`
+- Batch C PR: `feat/issue-251-batch-3-lobby-join-start-release-readiness`
+
+Hver PR skal linke tilbage til issue #251 og inkludere test-evidence + rollback-check.
+
+## Merge-gate for alle 3 batches
+- Små PRs (mål: reviewbar størrelse, helst < ~300 netto-linjer når muligt).
+- Grøn CI/checks før review-request.
+- Tydelig PR-beskrivelse med: scope, test evidence, out-of-scope.
+- Ingen skjulte sideeffekter på tværs af apps/domæner.

docs/ISSUE-252-REACT-FALLBACK-TRIGGERS-ARTIFACT.md

@@ -0,0 +1,27 @@
+# ISSUE-252 Artifact — React fallback trigger criteria (delivery-blocking only)
+
+Issue: **#252**
+
+## Leveret ændring
+Dokumentationen i `docs/spa-cutover-flag.md` er opdateret med en dedikeret sektion:
+- **React fallback trigger-kriterier (kun delivery-blocking)**
+- klare **tilladelses-kriterier** (alle skal være opfyldt)
+- tydelige **scope-limits**
+- eksplicitte **ikke-tilladte** anvendelser
+
+## Acceptance mapping
+1. **Clear trigger criteria**
+   - Definerer præcist hvornår fallback er tilladt:
+     - aktiv delivery-blocking fejl i Angular SPA
+     - ingen sikker Angular-fix inden release-vinduet
+     - rollback alene er utilstrækkelig for leveringsbehovet
+     - beslutning + evidens logges eksplicit (inkl. issue/incident-reference)
+2. **Scope limits**
+   - Begrænset til delivery-blocking host/player-paths.
+   - Ingen feature-bundling eller ikke-kritiske ændringer.
+   - Midlertidig anvendelse kun i aktiv incident/release-vindue.
+3. **When fallback is allowed**
+   - Kun når alle trigger-kriterier er opfyldt og dokumenteret.
+
+## Resultat
+Issue #252 er dokumenteret med operationelle guardrails, så React fallback kun bruges i kontrollerede, leveringsblokerende situationer.

docs/ISSUE-257-SHARED-I18N-KEYSPACE-FRONTEND-LOADER-ARTIFACT.md

@@ -0,0 +1,32 @@
+# ISSUE-257 Artifact — Shared i18n keyspace + frontend loader (da/en, Angular-first)
+
+Issue: **#257** (`[MVP][READY] #175-B: Shared i18n keyspace + frontend loader`)
+
+## Acceptance checklist
+
+- [x] **Delt key-strategi dokumenteret (frontend/backend)**
+  - Arkitektur/deling beskrevet i `docs/I18N_ARCHITECTURE.md`.
+  - Shared contract + keyspace source of truth: `shared/i18n/lobby.json`.
+
+- [x] **Frontend loader kan indlæse da+en med samme keyspace**
+  - Shared loader: `frontend/shared/i18n/lobby-loader.ts`.
+  - Angular-first integration via `frontend/angular/src/app/lobby-i18n.ts` (samme loader/samme keyspace).
+  - Locale-normalisering inkluderer underscore/hyphen variants (`da_DK` → `da`).
+
+- [x] **Minimal check for key-paritet da/en**
+  - `collectLocaleParityIssues(...)` i shared loader.
+  - Testet i `frontend/tests/lobby-loader.parity.test.ts`.
+
+- [x] **Ingen API-kontraktbrud**
+  - Contract-test: `frontend/tests/lobby-i18n.contract.test.ts`.
+  - Drift-check mellem manifest og katalog: `scripts/check_i18n_drift.py`.
+
+## Kørte checks
+
+```bash
+python3 scripts/check_i18n_drift.py
+cd frontend && npm test -- --run tests/lobby-loader.parity.test.ts tests/lobby-i18n.contract.test.ts
+cd frontend/angular && npm test -- --run src/app/lobby-i18n.spec.ts src/app/i18n-mvp-flow-smoke.spec.ts
+```
+
+Resultat: alle checks grønne.

docs/ISSUE-257-SHARED-I18N-LOADER-ARTIFACT.md

@@ -0,0 +1,37 @@
+# ISSUE-257 Artifact — shared i18n keyspace + frontend loader (Angular-first)
+
+Issue: **#257** (`[MVP][READY] #175-B: Shared i18n keyspace + frontend loader (da/en, Angular-first)`)
+
+## Acceptance mapping
+
+### 1) Delt key-strategi dokumenteret (frontend/backend)
+- Shared contract source: `shared/i18n/lobby.json`
+- Architecture doc: `docs/I18N_ARCHITECTURE.md`
+- Key-map/contract doc: `docs/ISSUE-226-SHARED-KEYMAP-LOCALE-CONTRACT.md`
+
+### 2) Frontend loader kan indlæse da+en med samme keyspace
+- Shared loader: `frontend/shared/i18n/lobby-loader.ts`
+- Angular-first consumer path:
+  - `frontend/src/spa/lobby-i18n.ts`
+  - Angular shell/tests continue to consume same shared catalog through shared loader contract.
+
+### 3) Minimal check for key-paritet da/en
+- Guard test: `frontend/tests/lobby-loader.parity.test.ts`
+- Contract test: `frontend/tests/lobby-i18n.contract.test.ts`
+
+### 4) Ingen API-kontraktbrud
+- Frontend API contract smoke:
+  - `frontend/angular/src/app/api-contract-smoke.spec.ts`
+  - `frontend/tests/angular-api-client.test.ts`
+
+## Verification run (this lane)
+
+```bash
+cd frontend
+npm test -- --run tests/lobby-loader.parity.test.ts tests/lobby-i18n.contract.test.ts tests/angular-api-client.test.ts
+
+cd ../frontend/angular
+npm test -- --run src/app/api-contract-smoke.spec.ts
+```
+
+Result: PASS (all selected suites green).

docs/ISSUE-260-PHONE-CLIENT-NO-AUDIO-GUARD-ARTIFACT.md

@@ -0,0 +1,18 @@
+# Issue #260 Artifact — Phone/client no-audio guard (primary-device only playback)
+
+## Scope
+Added regression coverage for MVP audio policy to ensure phone/client flows never claim playback ownership, while primary-device playback stays unaffected.
+
+## Acceptance mapping
+1. **client/phone triggers no playback**
+   - Existing test coverage retained in `player-shell.component.spec.ts`:
+     - `does not trigger original media play during player-shell init path`
+     - `installs secondary-device audio guard while player shell is mounted`
+2. **primary device playback unaffected**
+   - New negative test in `player-shell.component.spec.ts`:
+     - `keeps primary-device playback untouched when no-audio capability is disabled`
+3. **one negative test for phone audio**
+   - Existing negative path preserved:
+     - `does not trigger original media play during player-shell init path`
+4. **no backend contract changes**
+   - Frontend test/docs-only scope; no backend contract files changed.

docs/ISSUE-277-SHARED-I18N-PARITY-ARTIFACT.md

@@ -0,0 +1,80 @@
+# ISSUE-277 Artifact — shared i18n registry parity report (Django ↔ Angular MVP)
+
+Issue: **#277** (`[READY][#175][P3] Shared i18n registry artifact: backend/frontend keyspace parity report`)
+
+## Artifact metadata
+
+- `artifact_id`: `issue-277-shared-i18n-parity-report`
+- `artifact_version`: `1.0`
+- `catalog_source`: `shared/i18n/lobby.json`
+- `generator`: `scripts/report_i18n_parity.py`
+
+## Naming/version rules (email-manager-inspired strategy)
+
+- **Single canonical artifact per issue**: issue-bundne rapporter navngives `docs/ISSUE-<nr>-<slug>-ARTIFACT.md`.
+- **Stable artifact identity**: `artifact_id` ændres ikke ved tekstlige opdateringer i samme rapporttype; det er den faste reference i review/ops.
+- **Explicit artifact versioning**: `artifact_version` bumpes, når rapportlogik eller scope ændres, så drift/review kan se forskel på format- vs. dataændringer.
+- **Shared namespace first**: keys refereres med fulde navnerum (`frontend.ui.*`, `frontend.errors.*`, `backend.error_codes.*`, `backend.errors.*`) i stedet for lokale aliases i artefakter.
+- **Source-of-truth before consumers**: rapporten afledes fra `shared/i18n/lobby.json`; Django/Angular beskrives som consumers af samme registry og ikke som parallelle kontrakter.
+
+## MVP-critical parity summary
+
+- Frontend UI gameplay keys checked: **16** → `OK`
+- Frontend error keys checked: **7** → `OK`
+- Backend gameplay/error codes checked: **9** → `OK`
+- Distinct frontend error keys reached from backend MVP flow: **6** (`join_failed, nickname_invalid, nickname_taken, session_code_required, session_not_found, start_round_failed`)
+
+Status: **Shared locale matrix is aligned (`en`, `da`) and backend→frontend error handling is contract-complete for MVP-critical flow.**
+
+## Django ↔ Angular parity matrix (MVP-critical error contract)
+
+| Backend code (`backend.error_codes.*`) | Django message key (`backend.errors.*`) | Angular key (`frontend.errors.*`) | Locales `en/da` | Parity note |
+|---|---|---|---|---|
+| `session_code_required` | `session_code_required` | `session_code_required` | `OK` | 1:1 |
+| `nickname_invalid` | `nickname_invalid` | `nickname_invalid` | `OK` | 1:1 |
+| `session_not_found` | `session_not_found` | `session_not_found` | `OK` | 1:1 |
+| `session_not_joinable` | `session_not_joinable` | `join_failed` | `OK` | mapped alias |
+| `nickname_taken` | `nickname_taken` | `nickname_taken` | `OK` | 1:1 |
+| `category_slug_required` | `category_slug_required` | `start_round_failed` | `OK` | many:1 collapse |
+| `category_not_found` | `category_not_found` | `start_round_failed` | `OK` | many:1 collapse |
+| `round_start_invalid_phase` | `round_start_invalid_phase` | `start_round_failed` | `OK` | many:1 collapse |
+| `round_already_configured` | `round_already_configured` | `start_round_failed` | `OK` | many:1 collapse |
+
+## Scope notes
+
+- **Django** consumes backend codes/messages directly from `shared/i18n/lobby.json` via `lobby/i18n.py`.
+- **Angular** consumes the same registry via `frontend/shared/i18n/lobby-loader.ts` and runtime helpers in `frontend/angular/src/app/lobby-i18n.ts`.
+- **Parity in MVP** is therefore strongest on the shared error contract and locale matrix; gameplay UI labels are frontend-owned but still live in the same registry.
+
+## Verified MVP gameplay UI keyspace present in the shared registry
+
+- `frontend.ui.host.title`
+- `frontend.ui.player.title`
+- `frontend.ui.common.session_code`
+- `frontend.ui.player.nickname`
+- `frontend.ui.player.join`
+- `frontend.ui.host.start_round`
+- `frontend.ui.host.show_question`
+- `frontend.ui.player.lie_label`
+- `frontend.ui.player.submit_lie`
+- `frontend.ui.player.submit_guess`
+- `frontend.ui.host.mix_answers`
+- `frontend.ui.host.calculate_scores`
+- `frontend.ui.host.load_scoreboard`
+- `frontend.ui.host.final_leaderboard`
+- `frontend.ui.player.final_leaderboard`
+- `frontend.ui.common.points_short`
+
+## Concrete deviations / follow-up items
+
+1. **Error granularity collapse remains intentional**: backend codes `category_slug_required, category_not_found, round_start_invalid_phase, round_already_configured` all map to `frontend.errors.start_round_failed`. Follow-up only if product wants case-specific Angular copy instead of one shared host failure message.
+2. **Frontend-only fallback copy is not mirrored in Django**: `frontend.errors.unknown` and `frontend.errors.session_fetch_failed` are Angular-side resilience keys, not backend contract keys. Follow-up if API responses should expose stable backend equivalents for these states.
+3. **Gameplay UI labels are registry-shared but not backend-rendered**: `frontend.ui.host.*`, `frontend.ui.player.*`, and `frontend.ui.common.*` are available in the shared artifact, but Django currently consumes only the backend error slice. Follow-up only if server-rendered views must guarantee the same UI label surface as Angular.
+
+## Re-run
+
+```bash
+python3 scripts/check_i18n_drift.py
+python3 scripts/report_i18n_parity.py
+python3 scripts/check_i18n_parity_artifact.py
+```

docs/ISSUE-278-SMOKE-E2E-GATE-ARTIFACT.md

@@ -0,0 +1,36 @@
+# Issue #278 Artifact — smoke/e2e gate for da+en locale flow and primary-only audio
+
+## Scope
+Acceptance for `[READY][#175][P4]`:
+1. Verify one MVP host+player smoke run in `en`.
+2. Verify one MVP host+player smoke run in `da`.
+3. Verify audio routing remains `primary-device only` so phone/player clients never take playback ownership.
+
+Dette er en gate-/evidensleverance. Ingen ny produktfunktion ud over test/verifikation.
+
+## Implemented smoke gate
+Angular smoke spec: `frontend/angular/src/app/i18n-mvp-flow-smoke.spec.ts`
+
+The gate now runs two explicit locale scenarios:
+- `en`: host refresh/start-round copy + player submit-guess copy
+- `da`: samme flow med dansk copy
+
+Audio-policy delen af samme smoke-spec verificerer:
+- host/primary playback path er uændret før player mount
+- player mount installerer no-audio guard på secondary device
+- guard fjernes igen ved unmount, så primary path fortsat er eneste aktive output
+
+## Recommended verification command
+Køres fra `frontend/angular`:
+
+```bash
+npm test -- --run src/app/i18n-mvp-flow-smoke.spec.ts src/app/lobby-i18n.spec.ts src/app/features/player/player-shell.component.spec.ts
+```
+
+## Why this is the gate
+- `i18n-mvp-flow-smoke.spec.ts` giver en lille, samlet smoke/e2e-lignende verifikation af host+player i begge locale-kontekster.
+- `lobby-i18n.spec.ts` holder shared locale propagation + contract fallback grøn.
+- `player-shell.component.spec.ts` dækker den dybere regressionflade for audio-guard på secondary device.
+
+## Conclusion
+Gate’en verificerer nu eksplicit begge locale-runs (`da` + `en`) og bekræfter primary-only audio routing i MVP-flowet.

docs/ISSUE-279-I18N-MVP-CLOSEOUT.md

@@ -0,0 +1,168 @@
+# ISSUE-279 — i18n MVP close-out note
+
+Issue: **#279** (`[READY][#175][P5] MVP close-out note: migration/changelog + release-readiness checklist for i18n`)
+
+## Scope
+
+Dette dokument lukker MVP-sporet for issue #175 med tre konkrete ting:
+
+1. en migrationsnote for release/deploy,
+2. changelog-indhold der kan genbruges i næste release-note,
+3. en release-readiness checkliste for i18n, forankret i et verificeret snapshot af `main` ved reviewtidspunktet.
+
+Repo-state ved review-opdatering:
+- `main` peger nu på merge commit `1bc4c27` (PR #283), og inkluderer også PR #282 via merge commit `6ad5430`.
+- Denne note er opdateret mod repo-tilstanden verificeret 2026-03-13 UTC, ikke en løbende garanti for senere `main`-ændringer.
+- Denne revision afløser de tidligere snapshot-antagelser fra PR-historikken, hvor #282/#283 endnu ikke var landet.
+- Der er ingen åbne release-afklaringer tilbage for PR #282/#283; begge er allerede landet på `main`.
+
+## Current i18n MVP state on `main`
+
+Følgende er allerede til stede på `main`:
+
+- **Shared contract** i `shared/i18n/lobby.json`
+  - default locale: `en`
+  - supported locales: `en`, `da`
+  - fælles frontend/backend keyspace + fallback-regler
+- **Django bootstrap** via `partyhub/i18n_bootstrap.py` og `partyhub/settings.py`
+  - `LocaleMiddleware` aktiv
+  - `LANGUAGE_CODE` + `LANGUAGES` bootstrappes fra shared catalog
+- **Backend locale/error flow** via `lobby/i18n.py`
+  - normalisering af locale-tags
+  - locale-aware fejlpayload med `error_code`, `error`, `locale`
+  - fallback til `en` når locale eller oversættelse mangler
+- **Angular MVP wiring** via
+  - `frontend/shared/i18n/lobby-loader.ts`
+  - `frontend/angular/src/app/lobby-i18n.ts`
+  - host/player shells med locale switch og shared copy-opslag
+- **Drift/parity guardrails**
+  - `shared/i18n/key-manifest.json`
+  - `scripts/check_i18n_drift.py`
+  - frontend parity/contract tests
+- **Existing documentation/artifacts**
+  - `docs/I18N_ARCHITECTURE.md`
+  - `docs/ISSUE-175-I18N-SHARED-CONTRACT-ARTIFACT.md`
+  - `docs/ISSUE-225-BACKEND-I18N-BASELINE-ARTIFACT.md`
+  - `docs/ISSUE-257-SHARED-I18N-KEYSPACE-FRONTEND-LOADER-ARTIFACT.md`
+  - `docs/ISSUE-207-I18N-AUDIO-SMOKE-ARTIFACT.md`
+  - `docs/i18n-drift-check.md`
+
+## Migration note for release
+
+### Schema impact
+
+**Der er ingen nye Django-migrations i selve i18n-MVP-sporet på `main`.**
+
+Den i18n-relaterede leverance ligger i shared catalog, locale-bootstrap, error-payload-kontrakt, Angular wiring og test/documentation. Den kræver derfor ikke en særskilt i18n-database-migration for at gå i release.
+
+### Release/deploy expectation
+
+Selv om issue #279 ikke introducerer schemaændringer, skal release-flow stadig følge repoets generelle migreringsgate:
+
+```bash
+python manage.py makemigrations --check --dry-run
+python manage.py migrate --check --noinput
+```
+
+Hvorfor: release-policyen kræver, at vi undgår code/schema drift, og staging-smoke-suiten forventer eksplicit migration consistency check.
+
+### Praktisk migrationskonklusion
+
+Til release-notes/deploy-runbook kan i18n-sporet beskrives sådan her:
+
+- **Migration impact:** none for i18n MVP itself
+- **Deploy requirement:** run standard Django migration consistency checks anyway
+- **Rollback note:** rollback er primært kode-/asset-baseret (shared catalog, frontend bundles, backend locale resolver), ikke schema-baseret
+
+## Suggested changelog content
+
+Følgende tekst kan bruges direkte i næste unreleased/release-sektion:
+
+```markdown
+### i18n
+- Shared da/en lobby i18n contract is now wired across Django and Angular MVP flows via `shared/i18n/lobby.json`.
+- Backend error payloads expose stable locale-aware fields (`error_code`, `error`, `locale`) with fallback to English for unsupported locales.
+- Angular host/player shells now consume shared i18n copy, persist preferred locale, and keep audio-policy messaging aligned with the shared catalog.
+- Added repo guardrails for i18n drift/parity through the shared key manifest, drift checker, and focused frontend/backend contract tests.
+- Release migration impact for the i18n MVP is **none** beyond the standard Django migration consistency checks.
+```
+
+Kort version til annoterede release-notes:
+
+```markdown
+## i18n MVP close-out
+- Shared da/en contract is active across backend + Angular MVP shell.
+- Locale fallback remains `en` for unsupported requests and missing translations.
+- No i18n-specific schema migration is required; keep standard `migrate --check --noinput` in release verification.
+```
+
+## Release-readiness checklist for i18n
+
+Status er vurderet mod verificeret snapshot `main@1bc4c27` (reviewet 2026-03-13 UTC, inkl. PR #282/#283).
+
+### 1) Shared contract and locale behavior
+
+- [x] Shared catalog findes i `shared/i18n/lobby.json`.
+- [x] Default/supported locales er dokumenteret og implementeret som `en` + `da`.
+- [x] Backend bruger shared contract til locale-aware fejlbeskeder.
+- [x] Frontend/Angular bruger shared loader + shared keyspace.
+- [x] Fallback-regel til `en` er dokumenteret og testet.
+
+### 2) Verification artifacts and local checks
+
+- [x] Arkitektur-note findes: `docs/I18N_ARCHITECTURE.md`.
+- [x] Baseline artifact for issue #175 findes.
+- [x] Backend artifact for issue #225 findes.
+- [x] Frontend/shared loader artifact for issue #257 findes.
+- [x] Drift-check dokumentation findes i `docs/i18n-drift-check.md`.
+- [x] Parity artifact fra issue #277 er på `main` via PR #282 (merge commit `6ad5430`).
+
+### 3) Code readiness on current branch topology
+
+- [x] Angular MVP host/player i18n flow er på `main` (PR #281).
+- [x] Shared locale/bootstrap wiring er på `main`.
+- [x] Django i18n hardening fra issue #275 er på `main` via PR #283 (merge commit `1bc4c27`).
+- [x] PR #283 er ikke længere en separat release-afklaring; hardeningen er allerede indarbejdet på `main`.
+
+### 4) Release gate before shipping i18n as “done”
+
+- [x] PR #282 er allerede merged, så parity-artifact-status er afklaret på `main`.
+- [x] PR #283 er allerede merged, så backend hardening-status er afklaret på `main`.
+- [ ] Kør drift-check fra repo root:
+  ```bash
+  python3 scripts/check_i18n_drift.py
+  ```
+- [ ] Kør backend i18n regressions:
+  ```bash
+  . .venv/bin/activate && python manage.py test \
+    partyhub.tests_i18n_bootstrap \
+    lobby.tests.I18nResolverTests
+  ```
+- [ ] Kør frontend shared-contract/parity checks:
+  ```bash
+  cd frontend && npm test -- --run \
+    tests/lobby-loader.parity.test.ts \
+    tests/lobby-i18n.contract.test.ts
+  ```
+- [ ] Kør Angular MVP locale smoke:
+  ```bash
+  cd frontend/angular && npm test -- --run \
+    src/app/lobby-i18n.spec.ts \
+    src/app/i18n-mvp-flow-smoke.spec.ts \
+    src/app/features/host/host-shell.component.spec.ts \
+    src/app/features/player/player-shell.component.spec.ts
+  ```
+- [ ] Bekræft standard migration consistency gate:
+  ```bash
+  . .venv/bin/activate && python manage.py makemigrations --check --dry-run
+  . .venv/bin/activate && python manage.py migrate --check --noinput
+  ```
+- [ ] Følg `docs/RELEASE_POLICY.md`: staging deploy, `/healthz`, smoke-resultat og changelog-reference før tag.
+
+## Close-out conclusion
+
+**Konklusion:** i18n-MVP'en er implementeret på `main`, og issue #279 leverer den manglende release-/migration-closeout dokumentation uden nye kodeændringer i app-logikken.
+
+PR #282 (parity artifact) og PR #283 (Django i18n hardening) er nu begge merged på `main`, så close-out-noten, changelog-teksten og release-readiness-checklisten kan behandles som indbyrdes konsistente for det verificerede snapshot.
+
+Det betyder, at de resterende release-gates for i18n nu er de almindelige verificeringstrin (drift-check, backend/frontend-smoke, migrations-konsistens, staging deploy og changelog-reference) — ikke længere afklaring af om #282/#283 skal lande.

docs/ISSUE-287-CANONICAL-ROUND-FLOW-BACKEND-ARTIFACT.md

@@ -0,0 +1,22 @@
+# Issue #287 — Canonical round-flow backend artifact
+
+## State-transition matrix
+
+| Trigger | From | To | Server-owned effect |
+|---|---|---|---|
+| `POST /lobby/sessions/{code}/rounds/start` | `lobby` | `lie` | Opretter `RoundConfig`, vælger/låser konkret `RoundQuestion`, eksponerer prompt + lie-deadline i samme svar |
+| Sidste gyldige `submit_lie` for aktivt spørgsmål | `lie` | `guess` | Dedupe/shuffle `correct_answer + lies`, persisterer `mixed_answers`, broadcaster `phase.guess_started` |
+| Sidste gyldige `submit_guess` for aktivt spørgsmål | `guess` | `reveal` | Beregner score deterministisk, persisterer `ScoreEvent` + opdaterede `Player.score`, returnerer canonical reveal payload |
+| Første canonical state-read efter resolved reveal (`session_detail`, og idempotent `GET /scoreboard` hvis state allerede er resolved) | `reveal` | `scoreboard` | Promoverer scoreboard som state, broadcaster `phase.scoreboard`, eksponerer leaderboard + readiness |
+| `POST /lobby/sessions/{code}/rounds/next` | `scoreboard` | `lie` | Increment round counter, kopierer seneste `RoundConfig`, vælger/låser næste spørgsmål i samme kategori og broadcaster `phase.lie_started` |
+| `POST /lobby/sessions/{code}/finish` | `scoreboard` | `finished` | Fryser slutresultat og returnerer final leaderboard |
+
+## Flow-log (happy path)
+
+1. Host starter runde med kategori.
+2. Server vælger straks spørgsmål og går i `lie`.
+3. Spillere sender løgne; sidste submission auto-advancer til `guess`.
+4. Spillere sender gæt; sidste submission auto-advancer til `reveal` og scorer runden.
+5. Næste canonical state-read promoverer resolved reveal til `scoreboard`; state findes uden separat debug-knap.
+6. Host kan nu kun vælge `next round` eller `finish game`.
+7. `next round` starter næste runde direkte i `lie` med nyt konkret spørgsmål; ingen mellem-hop tilbage til `lobby`.

docs/ISSUE-301-CLIENT-ACTION-GATING-ARTIFACT.md

@@ -0,0 +1,52 @@
+# Issue #301 Artifact — Client action gating from canonical phase state
+
+Refs: #287, #301
+
+## What changed
+
+Frontend host/player shells now prefer the canonical phase exposed by `phase_view_model.current_phase` when deciding:
+
+- which gameplay actions are enabled
+- whether reveal data should still be shown
+- which SPA hash-route should represent the active game state
+
+This tightens the #301 slice so the client stays aligned with backend canonicalisation even when `session.status` lags during reveal/scoreboard promotion.
+
+## Gated UI actions by phase
+
+### Lobby
+- **Host:** `startRound`
+- **Player:** `join`
+
+### Bluff / lie
+- **Host:** `showQuestion`
+- **Player:** `submitLie`
+- **Blocked:** guess submission, scoreboard load, next round, finish game
+
+### Guess
+- **Host:** `mixAnswers`, `calculateScores`
+- **Player:** `submitGuess`
+- **Blocked:** lie submission, scoreboard load, next round, finish game
+
+### Reveal
+- **Host:** `loadScoreboard`
+- **Player:** display-only reveal state
+- **Blocked:** start next round, finish game, guess/lie submission
+
+### Scoreboard
+- **Host:** `startNextRound`, `finishGame`
+- **Player:** display-only reveal/scoreboard state
+- **Blocked:** scoreboard reload, guess/lie submission
+
+## Test evidence
+
+Targeted tests added/updated for:
+
+- host shell canonical gating and route sync when `current_phase` differs from `session.status`
+- player shell canonical gating and route sync when `current_phase` differs from `session.status`
+- shared gameplay phase machine gating from canonical permissions
+- shared API mapper contract coverage, including reveal/scoreboard payload stability
+
+## Contract note
+
+No backend protocol redesign was introduced. This follow-up only preserves and consumes the existing canonical phase/action contract more strictly on the client side.

docs/ISSUE-302-CANONICAL-LOOP-EVIDENCE.md

@@ -0,0 +1,55 @@
+# Issue #302 Evidence — canonical bluff → guess → reveal → scoreboard regression
+
+## Runnable command
+
+```bash
+python manage.py migrate --noinput
+python manage.py smoke_staging --artifact docs/artifacts/issue-302-canonical-loop-smoke.json
+```
+
+`migrate` is the normal local bootstrap precondition when the database has not been initialized yet; the regression evidence itself is produced by `smoke_staging`.
+
+## What the regression proves
+
+`smoke_staging` now exercises one full canonical round and fails fast with step-specific diagnostics if any of these break:
+
+1. `start_round` lands the session in `lie` and returns a concrete `round_question_id`.
+2. Final `submit_lie` auto-advances the session to `guess` and exposes mixed answers containing both the correct answer and player bluffs.
+3. Final `submit_guess` auto-advances the session to `reveal` and returns the canonical reveal payload.
+4. The reveal payload includes:
+   - correct answer
+   - all lies
+   - all guesses
+   - fooled-player references for bluff hits
+5. The first canonical state read after reveal promotes the session to `scoreboard`.
+6. Scoreboard promotion preserves the same reveal payload and exposes a leaderboard with `scoreboard_ready=true`.
+
+## Artifact shape
+
+When `--artifact` is provided, the JSON file records:
+
+- the exact smoke command
+- session code and round question id
+- deterministic guess plan used to produce both bluff hits and one correct guess
+- per-step evidence for:
+  - `create_session`
+  - `join_players`
+  - `start_round`
+  - `auto_guess_transition`
+  - `submit_guesses`
+  - `auto_reveal_transition`
+  - `auto_scoreboard_transition`
+  - `finish_game`
+- reveal summary (`correct_answer`, lie/guess counts, fooled-player ids, correct guess player ids)
+- promoted scoreboard leaderboard payload
+
+## Targeted test coverage
+
+Backend regression coverage lives in `lobby/tests.py`:
+
+- `test_smoke_staging_command_runs_full_flow`
+- `test_smoke_staging_writes_phase_evidence_artifact_when_requested`
+
+Together they ensure the command stays runnable in normal workflow and that the evidence artifact contains phase-by-phase proof instead of only a generic pass/fail.
+
+Refs #287 #302

docs/ISSUE-310-HOST-TRANSITION-IDEMPOTENCY-ARTIFACT.md

@@ -0,0 +1,33 @@
+# Issue #310 — Host transition idempotency and error catalog
+
+## Scope
+
+This artifact hardens the two host-owned scoreboard exits in the canonical gameplay flow:
+
+- `POST /lobby/sessions/{code}/rounds/next`
+- `POST /lobby/sessions/{code}/finish`
+
+The goal is retry-safe host behavior when the scoreboard transition already succeeded server-side but the client retries because of a duplicate click, timeout, or lost response.
+
+## Transition contract
+
+| Endpoint | First valid transition | Idempotent replay state | Replay result | Broadcast behavior | Still-invalid states |
+|---|---|---|---|---|---|
+| `POST /lobby/sessions/{code}/rounds/next` | `scoreboard -> lie` | `lie` with persisted current-round bootstrap (`RoundConfig` + `RoundQuestion`) | `200 OK` with the same canonical next-round payload shape | `phase.lie_started` fires only on the first transition | `lobby`, `guess`, `reveal`, `finished` → `next_round_invalid_phase` |
+| `POST /lobby/sessions/{code}/finish` | `scoreboard -> finished` | `finished` | `200 OK` with the same final leaderboard payload shape | `phase.game_over` fires only on the first transition | `lobby`, `lie`, `guess`, `reveal` → `finish_game_invalid_phase` |
+
+## Error catalog notes
+
+No new backend error codes were introduced for this slice.
+
+The contract change is behavioral:
+
+- `next_round_invalid_phase` now means the session is in a phase where the scoreboard → next-round transition has **not** already been completed, or the expected bootstrap artifact for the already-started round is missing.
+- `finish_game_invalid_phase` now means the session is in a phase where the scoreboard → finish transition has **not** already been completed.
+- Successful replays are returned as normal `200 OK` canonical responses instead of phase errors.
+
+## Acceptance evidence
+
+- Repeated `rounds/next` calls after a successful scoreboard exit return the same canonical lie/bootstrap payload without incrementing the round twice.
+- Repeated `finish` calls after a successful scoreboard exit return the same finished leaderboard payload without rebroadcasting game-over.
+- Wrong-phase calls outside those replay states still return the existing shared error codes.

docs/ISSUE-312-LOBBY-FUPOGFAKTA-EXTRACTION-MAP.md

@@ -0,0 +1,202 @@
+# Issue #312 — FupOgFakta extraction map for logic currently living in `lobby/`
+
+Parent: #311  
+Issue: #312
+
+## Purpose
+
+This artifact documents the concrete FupOgFakta-specific logic that still lives in `lobby/`, separates it from true platform/session concerns, and names the intended destination ownership before any larger code move happens.
+
+It is intentionally an inventory + extraction plan only. It does **not** perform the full move.
+
+## Architectural boundary this map is enforcing
+
+The target boundary is already described in:
+
+- `docs/plans/2026-03-09-fupogfakta-game-engine-design.md`
+- `docs/plans/2026-03-09-fupogfakta-implementation-plan.md`
+- `docs/ARCHITECTURE.md`
+
+Those docs consistently describe:
+
+- `lobby/` as the **platform layer** for session lifecycle, player presence, host ownership, generic game-run orchestration, and transport-facing platform concerns.
+- `fupogfakta/` as the **game cartridge** that owns question selection rules, round config semantics, lie/guess/reveal/scoreboard flow, answer mixing, scoring, and game-specific response/event payloads.
+
+In other words:
+
+- **Platform (`lobby/`)** should know that a session exists and that a game can be started/observed.
+- **Cartridge (`fupogfakta/`)** should know what a lie is, what a guess is, how answers are mixed, when phases advance, and what payload shape those game phases expose.
+
+## Summary split
+
+### Generic platform/session concerns that belong in `lobby/`
+
+These are not FupOgFakta-specific and should remain platform-owned:
+
+- Session code parsing/generation:
+  - `lobby/views.py::_generate_session_code`
+  - `lobby/views.py::_normalize_session_code`
+  - `lobby/views.py::_create_unique_session_code`
+- Generic request parsing:
+  - `lobby/views.py::_json_body`
+- Session lifecycle and player presence endpoints:
+  - `lobby/views.py::create_session`
+  - `lobby/views.py::join_session`
+  - `lobby/views.py::session_detail` **only for the generic session/player shell part**
+- Generic ownership / host authorization checks
+- Generic session detail payload fields:
+  - `session.code`
+  - `session.status`
+  - `session.host_id`
+  - `session.current_round`
+  - `session.players_count`
+  - `players[].id|nickname|score|is_connected`
+- Generic i18n/error transport helper usage:
+  - `lobby/i18n.py`
+  - `api_error(...)`
+- Route mounting / namespace ownership in `lobby/urls.py` for platform routes only
+
+### FupOgFakta-specific logic currently misplaced in `lobby/`
+
+These items are game-cartridge logic and should move behind `fupogfakta/` ownership:
+
+- Round question selection by category and previously-used questions
+- Lie-phase payload construction and lie timer semantics
+- Mixed-answer preparation for bluff gameplay
+- Guess correctness / fooled-player detection
+- Bluff/correct-answer score resolution
+- Reveal payload construction
+- Reveal → scoreboard promotion rules
+- Start round / mix answers / submit lie / submit guess / calculate scores / reveal scoreboard / next round / finish game gameplay endpoints
+- Phase view-model booleans that encode FupOgFakta rules rather than generic platform readiness
+
+## Extraction map
+
+| Source file | Current function / concern | Why it is FupOgFakta-specific | Intended destination / owner |
+| --- | --- | --- | --- |
+| `lobby/views.py` | `_build_player_ref(player)` | Helper is only used to shape FupOgFakta reveal payloads; not a generic platform concern today. | `fupogfakta/serializers.py` or `fupogfakta/payloads.py` owned by cartridge. |
+| `lobby/views.py` | `_build_reveal_payload(round_question)` | Encodes FupOgFakta reveal contract: lies, guesses, fooled-player refs, correct answer, prompt. | `fupogfakta/payloads.py::build_reveal_payload` or equivalent cartridge response builder. |
+| `lobby/views.py` | `_build_leaderboard(session)` | Current implementation is generic-ish, but used exclusively by FupOgFakta scoreboard/finish flow and coupled to that response shape. | Short term: keep shared helper if multiple games will consume same contract; otherwise move to `fupogfakta/payloads.py` until a true shared scoreboard contract exists. |
+| `lobby/views.py` | `_get_current_round_question(session)` | Depends on FupOgFakta `RoundQuestion` model and current-round semantics. | `fupogfakta/services/rounds.py` or `fupogfakta/queries.py`. |
+| `lobby/views.py` | `_select_round_question(session, round_config)` | Implements FupOgFakta question selection rules by category, active questions, and not-yet-used question set. | `fupogfakta/services/rounds.py::select_round_question`. |
+| `lobby/views.py` | `_build_lie_started_payload(session, round_config, round_question)` | Builds a FupOgFakta event/response contract for lie phase, including category, prompt, lie deadline, round question id. | `fupogfakta/payloads.py::build_lie_started_payload`. |
+| `lobby/views.py` | `_prepare_mixed_answers(round_question)` | Bluff-answer dedupe and shuffle is core FupOgFakta gameplay logic. | `fupogfakta/services/answers.py::prepare_mixed_answers`. |
+| `lobby/views.py` | `_resolve_scores(session, round_question, round_config)` | Applies FupOgFakta scoring rules for correct guesses and successful bluffs; depends on `Guess`, `LieAnswer`, `ScoreEvent`, `points_correct`, `points_bluff`. | `fupogfakta/services/scoring.py::resolve_scores`. |
+| `lobby/views.py` | `_maybe_promote_reveal_to_scoreboard(session)` | Encodes FupOgFakta reveal completion semantics and scoreboard transition trigger. | `fupogfakta/services/phases.py::maybe_promote_reveal_to_scoreboard`. |
+| `lobby/views.py` | `_build_phase_view_model(session, players_count, has_round_question)` | Most booleans are not platform-generic; they encode FupOgFakta phase names (`lie`, `guess`, `scoreboard`) and MVP constraints (`3-5 players`, round-question readiness, next-round/finish gating). | Split: keep platform-shell fields in `lobby/`; move game-specific readiness/action flags to `fupogfakta/payloads.py::build_phase_view_model` or cartridge driver payload builder. |
+| `lobby/views.py` | `start_round(request, code)` | Starts FupOgFakta round, binds category, creates `RoundConfig`, selects `RoundQuestion`, transitions to `LIE`, broadcasts `phase.lie_started`. | `fupogfakta/views.py` or cartridge command handler behind a future `GameDriver.on_game_start` / round bootstrap service. |
+| `lobby/views.py` | `show_question(request, code)` | Emits lie-phase question payload using FupOgFakta `RoundQuestion` and `RoundConfig`. | `fupogfakta/views.py` or remove entirely once canonical driver flow owns the transition. |
+| `lobby/views.py` | `submit_lie(request, code, round_question_id)` | Pure FupOgFakta gameplay endpoint: lie validation, deadline semantics, auto-advance to guess phase, `phase.guess_started` payload. | `fupogfakta/views.py::submit_lie` (or cartridge intent handler). |
+| `lobby/views.py` | `mix_answers(request, code, round_question_id)` | Manual FupOgFakta host action for lie→guess transition and answer mixing. | `fupogfakta/views.py` short term; long term likely deleted in favor of cartridge-driven automatic transition. |
+| `lobby/views.py` | `submit_guess(request, code, round_question_id)` | Pure FupOgFakta gameplay endpoint: validates answer choice, resolves correctness/bluff source, auto-calculates scores, transitions to reveal. | `fupogfakta/views.py::submit_guess` plus `fupogfakta/services/scoring.py` and `fupogfakta/services/phases.py`. |
+| `lobby/views.py` | `reveal_scoreboard(request, code)` | FupOgFakta reveal/scoreboard progression, not a generic platform capability. | `fupogfakta/views.py::reveal_scoreboard` or cartridge phase service. |
+| `lobby/views.py` | `start_next_round(request, code)` | FupOgFakta next-round bootstrap: copies prior `RoundConfig`, increments round, picks next question, re-enters lie phase. | `fupogfakta/services/rounds.py::start_next_round` plus cartridge-owned endpoint/driver integration. |
+| `lobby/views.py` | `finish_game(request, code)` | Current finish path is tied to FupOgFakta scoreboard semantics and winner payload. | `fupogfakta/views.py::finish_game` until a truly generic platform finish contract exists. |
+| `lobby/views.py` | `calculate_scores(request, code, round_question_id)` | Explicit FupOgFakta score resolution endpoint. | `fupogfakta/services/scoring.py` and/or remove when fully absorbed by cartridge phase driver. |
+| `lobby/urls.py` | Gameplay routes for rounds, lies, guesses, scoreboard, finish | These route names expose FupOgFakta-specific phase/actions from the platform namespace. | Re-home under `fupogfakta/urls.py` or leave mounted under `/lobby/sessions/...` only as a temporary façade delegating to cartridge-owned code. |
+| `lobby/tests.py` | `StartRoundTests`, `LieSubmissionTests`, `MixAnswersTests`, `GuessSubmissionTests`, `CanonicalRoundFlowTests`, `ScoreCalculationTests`, `RevealRoundFlowTests`, `SessionDetailRoundQuestionTests`, `SessionDetailPhaseViewModelTests`, `SmokeStagingCommandTests` | These test classes verify FupOgFakta game flow rather than platform mechanics. | Move/split into `fupogfakta/tests/` with only session creation/join/platform transport tests left in `lobby/tests.py`. |
+| `lobby/management/commands/smoke_staging.py` | End-to-end gameplay smoke through lies/guesses/finish | Script executes one concrete game flow and should be cartridge-aware, not platform-owned. | `fupogfakta/management/commands/` or a shared smoke harness that delegates into cartridge-specific scenario runners. |
+
+## Recommended ownership split by module
+
+### Keep in `lobby/`
+
+- Session creation/join and session-code lifecycle
+- Generic player membership/presence reads
+- Generic auth/host checks helpers (if extracted from views)
+- Generic API error/i18n plumbing
+- Future `GameRun` / driver orchestration, timers, and cartridge dispatch
+- A slim generic `session_detail` envelope that can embed cartridge payloads under a dedicated game key
+
+### Move to `fupogfakta/`
+
+- Round state queries
+- Question selection
+- Lie/guess/reveal/scoreboard/finish transition rules
+- Score calculation
+- Answer mixing
+- Gameplay payload/response builders
+- Gameplay endpoints and tests
+- Gameplay smoke command
+
+## Explicit boundary for `session_detail`
+
+`session_detail` is currently mixed.
+
+### Generic part that should remain platform-owned
+
+- Session identity/status metadata
+- Player list / presence list
+- Generic host/player capability envelope if it is game-agnostic
+
+### FupOgFakta part that should move or be delegated
+
+- `round_question` payload
+- `reveal` payload
+- `scoreboard` payload
+- `phase_view_model` fields keyed to `lie`, `guess`, `scoreboard`, `finished`, `question_ready`, and 3–5-player MVP rules
+
+A clean future shape would be:
+
+```json
+{
+  "session": {"code": "ABC123", "status": "active", "game_type": "fupogfakta"},
+  "players": [...],
+  "game": {
+    "phase": "lie",
+    "payload": {"round_question": {...}, "reveal": null, "scoreboard": null}
+  }
+}
+```
+
+That makes `lobby/` the shell and `fupogfakta/` the authority for game-state payloads.
+
+## Concrete extraction sequence
+
+1. **Move pure helpers first**
+   - `_get_current_round_question`
+   - `_select_round_question`
+   - `_prepare_mixed_answers`
+   - `_resolve_scores`
+   - `_build_lie_started_payload`
+   - `_build_reveal_payload`
+2. **Move gameplay endpoints behind cartridge-owned service functions**
+   - `submit_lie`
+   - `submit_guess`
+   - `start_round`
+   - `start_next_round`
+   - `finish_game`
+   - `reveal_scoreboard`
+   - `calculate_scores`
+3. **Slim `session_detail` into platform envelope + delegated cartridge payload**
+4. **Move gameplay tests out of `lobby/tests.py`**
+5. **Optionally leave compatibility routes in `lobby/urls.py` as a façade** until clients are rewired
+
+## Risks this map is explicitly preventing
+
+- Moving only models but leaving hidden phase-transition rules in `lobby/views.py`
+- Treating `session_detail` as platform-generic while it still leaks cartridge payload semantics
+- Leaving scoreboard/reveal transition logic behind as an undocumented coupling
+- Splitting tests incorrectly so regressions stay "green" in `lobby/` while FupOgFakta behavior silently drifts
+
+## Decision
+
+For #311 / #312, the repository should treat the following as **game-specific and extraction candidates**:
+
+- round-question selection
+- lie/guess/reveal/scoreboard/finish transitions
+- answer mixing
+- score resolution
+- reveal/scoreboard payload builders
+- FupOgFakta-specific session-detail subpayloads
+- gameplay flow tests and smoke command
+
+And it should treat the following as **platform-generic**:
+
+- session identity/lifecycle
+- player presence/membership
+- host authorization shell
+- generic error transport
+- future game-driver dispatch/orchestration
+
+That is the explicit `lobby` vs `fupogfakta` boundary this issue needs before code extraction proceeds.

docs/STAGING_GAMEPLAY_SMOKE_ARTIFACT.md

@@ -0,0 +1,66 @@
+# Staging gameplay smoke artifact (Issue #144)
+
+Formål: levere et lille, ensartet evidensformat for release-nær gameplay-smoke i #16/#90-sporet uden scope-udvidelse.
+
+## Guardrails (MVP)
+- Hold scope inden for #16 (execution board) og #17 (scope guardrail).
+- Kun verifikation af eksisterende flow; ingen nye features/polish.
+
+## Hvornår bruges artifacten
+- Efter staging-smoke af gameplay-flowet: lobby -> join -> start -> runde -> scoreboard -> next/final.
+- Resultatet logges i issue/PR-kommentar med denne skabelon.
+
+## Evidence template (kopiér i PR/issue-kommentar)
+```markdown
+### Staging gameplay smoke evidence
+- Timestamp (UTC): <YYYY-MM-DD HH:MM>
+- Environment: staging
+- Commit/Head SHA: <sha>
+- Linked scope: #16 #17 #90 #129 #144
+
+#### Setup
+- Host authenticated in Django admin: <yes/no>
+- Active category/questions present: <yes/no>
+- Participants: host + <N> players
+- `USE_SPA_UI`: <on/off>
+- `WPP_SPA_ASSET_VERSION`: <release-token/sha>
+- UI route used:
+  - OFF (legacy): `/lobby/ui/host` + `/lobby/ui/player`
+  - ON (SPA shell): `/lobby/ui/host/<spa-path>` + `/lobby/ui/player`
+
+#### Checks (PASS/FAIL)
+0. Same release-window verification
+   - OFF + ON smoke kørt i samme release-vindue: <pass/fail>
+1. Cutover route sanity
+   - Flag OFF serves legacy UI templates: <pass/fail>
+   - Flag ON serves SPA shell on expected path(s): <pass/fail>
+2. Lobby -> join -> start
+   - Mixed-case + whitespace session code accepted: <pass/fail>
+3. One full round to scoreboard
+   - submit lie -> mix -> submit guess -> calculate score -> show scoreboard: <pass/fail>
+4. Next-round + game-end sanity
+   - next round transitions: <pass/fail>
+   - final leaderboard visible: <pass/fail>
+
+#### Smoke-gate decision (før `USE_SPA_UI=true`)
+- Gate status: <GREEN/RED>
+- Gate criteria met:
+  - [ ] Cutover route sanity = PASS (OFF + ON)
+  - [ ] Full gameplay round = PASS
+  - [ ] Next-round/final leaderboard sanity = PASS
+  - [ ] Ingen nye blocker-regressioner i host/player flow
+
+#### Rollback checkpoint
+- Rollback required: <yes/no>
+- Trigger reason (if yes): <kort trigger>
+- Rollback done (`USE_SPA_UI=false`) verified: <yes/no>
+
+#### Evidence pointers
+- Command(s): `<exact command(s)>`
+- UI notes/screenshots/log refs: <short refs>
+- Result: <PASS/FAIL>
+- If FAIL: blocker issue link + shortest repro
+```
+
+## Anti-stall minimum
+Hvis der ikke er ny kode at ændre, er denne artifact-skabelon den mindste gyldige leverance for at sikre ensartet, reviewbar smoke-evidens i staging.

docs/UI_SMOKE.md

@@ -4,15 +4,45 @@
 - Host er logget ind i Django.
 - Mindst én aktiv kategori med spørgsmål findes.
 
+## Cutover-forudsætning (`USE_SPA_UI`)
+- `USE_SPA_UI=false` (default): brug legacy routes `/lobby/ui/host` + `/lobby/ui/player`.
+- `USE_SPA_UI=true`: host må gerne testes på SPA deep-link route `/lobby/ui/host/<spa-path>` (fx `/lobby/ui/host/guess`), player på `/lobby/ui/player`.
+
 ## Flow
-1. Åbn host-siden på /lobby/ui/host og tryk Opret session.
-2. Åbn player-siden i 3 faner/enheder på /lobby/ui/player.
-3. Join alle spillere med sessionkode og nickname.
-4. Host: vælg kategori, Start runde, Vis spørgsmål.
-5. Spillere: brug round_question_id og submit løgn.
-6. Host: Mix svar.
-7. Spillere: submit gæt.
-8. Host: Beregn score og Vis scoreboard.
-9. Host: Næste runde eller Afslut spil.
+1. Verificér cutover-route matcher valgt flag (legacy vs SPA shell).
+2. Åbn host-siden og tryk Opret session.
+3. Åbn player-siden i 3 faner/enheder.
+4. Join alle spillere med sessionkode og nickname.
+5. Host: vælg kategori, Start runde, Vis spørgsmål.
+6. Spillere: brug round_question_id og submit løgn.
+7. Host: Mix svar.
+8. Spillere: submit gæt.
+9. Host: Beregn score og Vis scoreboard.
+10. Host: Næste runde eller Afslut spil.
+
+## Smoke-gate (staging cutover)
+`USE_SPA_UI` må kun aktiveres i staging når følgende er opfyldt:
+- Cutover route sanity er PASS for både OFF (legacy) og ON (SPA shell).
+- Én fuld gameplay-runde til scoreboard er PASS.
+- Next-round/final leaderboard sanity er PASS.
+- Ingen nye blocker-regressioner i host/player kerneflow.
+
+## Samme release-vindue: SPA OFF + ON verifikation
+Kør begge checks i samme release-vindue (samme deploy/artifact version):
+
+1. **OFF-pass (legacy)**
+   - `USE_SPA_UI=false`
+   - Verificér legacy routes + fuld runde.
+2. **ON-pass (SPA)**
+   - `USE_SPA_UI=true`
+   - Behold samme release artifact og kun toggl flag/version-token ved behov.
+   - Verificér SPA shell routes + fuld runde.
+3. Dokumentér begge pass i samme smoke-artifact med UTC timestamps og `WPP_SPA_ASSET_VERSION`.
+
+## Rollback check points
+Skift straks tilbage til `USE_SPA_UI=false` hvis en gate fejler:
+1. Verificér legacy routes (`/lobby/ui/host` + `/lobby/ui/player`) fungerer igen.
+2. Log rollback trigger + kort repro i smoke artifact.
+3. Opret/link blocker issue før nyt cutover-forsøg.
 
 Resultat: En fuld runde kan køres uden rå API-kald fra terminal.

docs/artifacts/issue-302-canonical-loop-smoke.json

@@ -0,0 +1,110 @@
+{
+  "ok": true,
+  "command": "python manage.py smoke_staging --artifact <path>",
+  "generated_at": "2026-03-16T15:19:30.105231+00:00",
+  "question": {
+    "prompt": "Smoke prompt?",
+    "correct_answer": "Correct"
+  },
+  "steps": [
+    {
+      "step": "create_session",
+      "session_status": "lobby"
+    },
+    {
+      "step": "join_players",
+      "players_count": 3
+    },
+    {
+      "step": "start_round",
+      "session_status": "lie",
+      "round_question_id": 1
+    },
+    {
+      "step": "auto_guess_transition",
+      "session_status": "guess",
+      "answers": [
+        "Lie from P3",
+        "Lie from P1",
+        "Lie from P2",
+        "Correct"
+      ]
+    },
+    {
+      "step": "submit_guesses",
+      "guess_results": [
+        {
+          "player_id": 1,
+          "selected_text": "Lie from P2",
+          "is_correct": false,
+          "fooled_player_id": 2
+        },
+        {
+          "player_id": 2,
+          "selected_text": "Correct",
+          "is_correct": true,
+          "fooled_player_id": null
+        },
+        {
+          "player_id": 3,
+          "selected_text": "Lie from P1",
+          "is_correct": false,
+          "fooled_player_id": 1
+        }
+      ]
+    },
+    {
+      "step": "auto_reveal_transition",
+      "session_status": "reveal",
+      "reveal": {
+        "correct_answer": "Correct",
+        "lies_count": 3,
+        "guesses_count": 3,
+        "fooled_player_ids": [
+          1,
+          2
+        ],
+        "correct_guess_player_ids": [
+          2
+        ]
+      }
+    },
+    {
+      "step": "auto_scoreboard_transition",
+      "session_status": "scoreboard",
+      "leaderboard": [
+        {
+          "id": 2,
+          "nickname": "P2",
+          "score": 7
+        },
+        {
+          "id": 1,
+          "nickname": "P1",
+          "score": 2
+        },
+        {
+          "id": 3,
+          "nickname": "P3",
+          "score": 0
+        }
+      ]
+    },
+    {
+      "step": "finish_game",
+      "session_status": "finished"
+    }
+  ],
+  "session_code": "7YV59E",
+  "players": [
+    "P1",
+    "P2",
+    "P3"
+  ],
+  "round_question_id": 1,
+  "guess_plan": {
+    "P1": "Lie from P2",
+    "P2": "Correct",
+    "P3": "Lie from P1"
+  }
+}

docs/i18n-drift-check.md

@@ -0,0 +1,34 @@
+# i18n key manifest + drift check
+
+Issue: #240
+
+This repo keeps shared lobby keyspaces in two files:
+
+- Contract source: `shared/i18n/lobby.json`
+- Key manifest: `shared/i18n/key-manifest.json`
+
+The manifest is intentionally small and explicit. It lists:
+
+- Supported locales (`locales`)
+- Frontend error key set (`frontend_error_keys`)
+- Backend error code set (`backend_error_codes`)
+- Backend translation key set (`backend_error_keys`)
+- Optional contract-only aliases (`allowed_contract_only_backend_codes`)
+
+## Local check
+
+Run the read-only drift checker from repo root:
+
+```bash
+python3 scripts/check_i18n_drift.py
+```
+
+The script returns non-zero when it detects drift, including:
+
+- key set mismatch between manifest and shared catalog
+- missing backend→frontend mapping coverage
+- mapping to unknown frontend keys
+- mappings for unknown backend codes
+- missing/empty locale translations (`en`/`da`)
+
+No CI gating changes are included in this task; this is a local guardrail.

docs/i18n-keymap.md

@@ -0,0 +1,69 @@
+# i18n key-map bootstrap (Angular host/player MVP)
+
+Issue: #220  
+Scope: Lobby → Join → Start round → Round → Reveal → Scoreboard  
+Locales: `en`, `da`
+
+This document is the gameplay key-namespace map for Angular host/player MVP.
+It maps existing text keys only (no feature expansion) and stays aligned with `shared/i18n/lobby.json`.
+
+## Key families
+
+- `host` — `frontend.ui.host.*` host-facing gameplay actions and status text.
+- `player` — `frontend.ui.player.*` player-facing gameplay actions and status text.
+- `system` — shared UI labels used across host/player views (implemented under `frontend.ui.common.*` in `shared/i18n/lobby.json`).
+- `errors` — user-facing error keys shown by frontend (`frontend.errors.*`) plus backend code → frontend key bridge via `backend.error_codes.*` / `contract.backend_to_frontend_error_keys.*`.
+
+## Gameplay flow key map
+
+| Flow step | Family | Key | en | da |
+|---|---|---|---|---|
+| Lobby | `host` | `host.title` | Host gameplay flow | Vært gameplay-flow |
+| Lobby | `player` | `player.title` | Player gameplay flow | Spiller gameplay-flow |
+| Lobby | `system` (`frontend.ui.common`) | `common.session_code` | Session code | Sessionskode |
+| Lobby | `player` | `player.nickname` | Nickname | Kaldenavn |
+| Join | `player` | `player.join` | Join | Join |
+| Start round | `host` | `host.start_round` | Start round | Start runde |
+| Round | `host` | `host.show_question` | Show question | Vis spørgsmål |
+| Round | `player` | `player.lie_label` | Lie | Løgn |
+| Round | `player` | `player.submit_lie` | Submit lie | Send løgn |
+| Round | `player` | `player.submit_guess` | Submit guess | Send gæt |
+| Reveal | `host` | `host.mix_answers` | Mix answers → guess | Bland svar → gæt |
+| Reveal | `host` | `host.calculate_scores` | Calculate scores → reveal | Udregn score → afslør |
+| Scoreboard | `host` | `host.load_scoreboard` | Load scoreboard | Hent scoreboard |
+| Scoreboard | `host` | `host.final_leaderboard` | Final leaderboard | Finale leaderboard |
+| Scoreboard | `player` | `player.final_leaderboard` | Final leaderboard | Finale leaderboard |
+| Scoreboard | `system` (`frontend.ui.common`) | `common.points_short` | pts | point |
+
+## Frontend error keys used in flow scope
+
+| Error family | Key | en | da |
+|---|---|---|---|
+| Join | `frontend.errors.session_code_required` | Session code is required. | Sessionskoden er påkrævet. |
+| Join | `frontend.errors.session_not_found` | Session code is invalid or the session no longer exists. | Sessionskoden er ugyldig, eller sessionen findes ikke længere. |
+| Join | `frontend.errors.nickname_invalid` | Nickname must be between 2 and 40 characters. | Kaldenavn skal være mellem 2 og 40 tegn. |
+| Join | `frontend.errors.nickname_taken` | Nickname is already taken. | Kaldenavnet er allerede taget. |
+| Join | `frontend.errors.join_failed` | Join failed. Check code or nickname and try again. | Kunne ikke joine. Tjek kode eller kaldenavn og prøv igen. |
+| Start round | `frontend.errors.start_round_failed` | Could not start round. Refresh the lobby and try again. | Kunne ikke starte runden. Opdater lobbyen og prøv igen. |
+| Any | `frontend.errors.unknown` | Action failed. Refresh status and try again. | Handlingen fejlede. Opdater status og prøv igen. |
+
+## Backend→frontend mapping for gameplay errors
+
+Mapped in `contract.backend_to_frontend_error_keys` (source: `shared/i18n/lobby.json`):
+
+> Note: `host_only_action` is **not** part of the current shared contract mapping and is intentionally not listed here.
+
+- `session_code_required` → `session_code_required`
+- `nickname_invalid` → `nickname_invalid`
+- `session_not_found` → `session_not_found`
+- `session_not_joinable` → `join_failed`
+- `nickname_taken` → `nickname_taken`
+- `category_slug_required` → `start_round_failed`
+- `category_not_found` → `start_round_failed`
+- `round_start_invalid_phase` → `start_round_failed`
+- `round_already_configured` → `start_round_failed`
+
+## Notes
+
+- This is a bootstrap key-map doc for MVP mergeability.
+- The key/value source of truth remains `shared/i18n/lobby.json`.

docs/issue-180-flow-log.md

@@ -0,0 +1,28 @@
+# Issue #180 – SPA gameplay flow evidence
+
+## Flow log (host + player, no page reload)
+
+1. Host opens SPA host shell and loads scoreboard (`GET /lobby/sessions/{code}/scoreboard`).
+2. Host starts next round (`POST /lobby/sessions/{code}/rounds/next`).
+3. Host shell refreshes session state in-place (`GET /lobby/sessions/{code}`) and clears old scoreboard/final leaderboard payloads.
+4. Player shell performs periodic session refresh while online (3s cadence) and transitions from `scoreboard` to `lobby` without page reload.
+5. Host finishes game (`POST /lobby/sessions/{code}/finish`) and renders final leaderboard directly in SPA shell.
+6. Player shell reads `finished` state and renders final leaderboard in SPA (sorted by score).
+7. Error/retry paths available:
+   - Host: next-round and finish-game retry buttons with explicit error feedback.
+   - Player: reconnect + submit retry feedback.
+
+## Test output snapshot
+
+Command:
+
+```bash
+cd frontend/angular
+npm test -- --run src/app/features/host/host-shell.component.spec.ts src/app/features/player/player-shell.component.spec.ts
+```
+
+Result:
+
+- `host-shell.component.spec.ts`: 6 passed
+- `player-shell.component.spec.ts`: 7 passed
+- Total: 13 passed, 0 failed

docs/plans/2026-03-09-fupogfakta-game-engine-design.md

@@ -0,0 +1,272 @@
+# Design: Fup og Fakta — Game Engine & Platform Architecture
+
+**Date:** 2026-03-09
+**Status:** Approved
+
+---
+
+## Overview
+
+Build a working Fup og Fakta game (Fibbage-style) on top of a **pluggable game platform**. The platform handles sessions, players, WebSocket push, and Celery-driven timers. Each game is a self-contained **cartridge** that implements a shared driver interface and owns its own models, config, and phase logic.
+
+---
+
+## Platform Architecture
+
+```
+partyhub/     Django project — settings, Celery app, ASGI
+lobby/        Platform layer — sessions, players, GameRun, timer dispatch
+realtime/     WebSocket consumers (already built)
+fupogfakta/   Game cartridge #1
+future_game/  Game cartridge #N (same interface)
+```
+
+### Platform provides (`lobby/`)
+
+#### Models
+
+**`GameSession`** (exists, minor additions)
+- `game_type` (CharField) — e.g. `"fupogfakta"`
+- `host` (FK → User)
+- `code` (6-char session code)
+- `status` (LOBBY / ACTIVE / FINISHED)
+- `config_id` / `config_snapshot` — see Config section
+
+**`GameRun`** (new — ephemeral, deleted on game exit)
+- `session` (OneToOne → GameSession)
+- `current_state` (CharField — game-defined state string)
+- `phase_deadline` (DateTimeField, nullable)
+- `is_paused` (BooleanField, default False)
+- `paused_remaining_seconds` (FloatField, nullable)
+- `celery_task_id` (CharField, nullable)
+- `state_data` (JSONField) — game-specific snapshot for current phase
+
+**`Player`** (exists)
+- `session`, `nickname`, `score`, `session_token`, `is_connected`
+
+#### GameDriver interface
+
+Each cartridge implements:
+
+```python
+class GameDriver:
+    game_type: str                        # e.g. "fupogfakta"
+
+    def on_game_start(session, run, config) -> PhaseResult
+    def on_timer_expired(session, run, config) -> PhaseResult
+    def on_pause(session, run) -> None
+    def on_resume(session, run) -> None
+    def on_exit(session, run) -> None     # must clean up all game data
+    def get_ws_payload(state, state_data) -> dict
+```
+
+`PhaseResult` = `(next_state: str, duration_seconds: int | None, broadcast_payload: dict)`
+
+#### Celery task
+
+```python
+@app.task
+def handle_timer_expired(run_id: int, expected_state: str):
+    # If run no longer exists or state has changed → stale task, ignore
+    # Call driver.on_timer_expired(session, run, config)
+    # Apply PhaseResult: update run, broadcast via channel layer, schedule next task
+```
+
+`expected_state` prevents stale tasks from firing after pause/resume or manual state changes.
+
+#### REST endpoints (platform-level)
+
+- `POST /sessions/{code}/play` — start or resume
+- `POST /sessions/{code}/pause` — pause current phase timer
+- `POST /sessions/{code}/exit` — end game, delete GameRun + all game data
+
+---
+
+## Configuration System
+
+### Base config model (`partyhub/`)
+
+```python
+class BaseGameConfig(models.Model):
+    class Meta:
+        abstract = True
+
+    name = models.CharField(max_length=100)          # "Quick game", "Full evening"
+    user = models.ForeignKey(User, null=True, ...)    # null = system default
+    is_default = models.BooleanField(default=False)
+    created_at = models.DateTimeField(auto_now_add=True)
+```
+
+### Game-specific config (`fupogfakta/`)
+
+```python
+class FupOgFaktaConfig(BaseGameConfig):
+    num_rounds               = PositiveIntegerField(default=3)
+    questions_per_round      = PositiveIntegerField(default=3)
+    min_players              = PositiveIntegerField(default=2)
+    max_players              = PositiveIntegerField(default=8)
+    lie_seconds              = PositiveIntegerField(default=45)
+    guess_seconds            = PositiveIntegerField(default=30)
+    reveal_seconds_per_lie   = PositiveIntegerField(default=8)
+    scoreboard_recap_seconds = PositiveIntegerField(default=10)
+    # Escalating scoring per round (stored as arrays or separate fields)
+    points_correct           = JSONField(default=[1500, 3000, 4500])
+    points_bluff             = JSONField(default=[500, 1000, 1500])
+    # Reaction bonus (static, feeds post-game awards only)
+    reaction_bonus           = IntegerField(default=5)
+```
+
+### Default resolution at session start
+
+1. User has `is_default=True` row for this game type → use that
+2. System default (`user=null, is_default=True`) — set in Django admin
+3. Model field `default=` values (hardcoded)
+
+User can have **multiple named presets** (one-to-many). When starting a session they choose which to use (or it auto-selects their default). The chosen config's values are **snapshotted into `GameRun.state_data`** at game start — immutable for the life of the session.
+
+---
+
+## Fup og Fakta — Game States
+
+```
+LOBBY
+  │ (host presses Play)
+  ▼
+LIE_PHASE         timer: lie_seconds
+  │ (all submitted OR timer expires)
+  ▼
+GUESS_PHASE       timer: guess_seconds
+  │ (timer expires — no mercy)
+  ▼
+REVEAL_LIE_{n}    timer: reveal_seconds_per_lie  (one per lie with ≥1 guess)
+  │                    → score liar incrementally as each is shown
+  ▼
+REVEAL_TRUTH      timer: reveal_seconds_per_lie
+  │                    → score correct guessers
+  ▼
+SCOREBOARD_RECAP  timer: scoreboard_recap_seconds
+  │
+  ├─ more questions in round → back to LIE_PHASE (next question)
+  ├─ round done, more rounds → back to LIE_PHASE (next round, next category)
+  └─ all rounds done → POST_GAME_AWARDS
+       timer: configurable
+       → FINISHED (GameRun deleted, GameSession status = FINISHED)
+```
+
+---
+
+## Fup og Fakta — Phase Details
+
+### LIE_PHASE
+- Question shown to all clients via WebSocket (`phase.lie_started` event)
+- Players submit lie via `POST /fupogfakta/{code}/lie`
+- **If lie matches correct answer (case-insensitive):** return `error_code: lie_matches_correct_answer` — player prompted again, does not consume their submission
+- Anonymous to other players during this phase
+- `state_data` tracks: question id, round number, how many have submitted (for progress display on host screen)
+- Timer expires → transition to GUESS_PHASE regardless of how many submitted
+
+### GUESS_PHASE
+- Answers mixed (lies + truth, deduped) broadcast to all clients (`phase.guess_started`)
+- Players guess via `POST /fupogfakta/{code}/guess`
+- **After selecting:** player can react to other lies with 👍 😂 ❤️ etc. until timer expires. Cannot change guess.
+- Reactions stored in `LieReaction` model (player, lie, reaction_type)
+- Timer expires → transition to first REVEAL_LIE (or REVEAL_TRUTH if no lies had guesses)
+
+### REVEAL_LIE_{n}
+- One Celery task per lie to reveal (only lies with ≥1 guesser)
+- Broadcast: which lie, who wrote it, who guessed it (`phase.reveal_lie`)
+- Score awarded to liar: `points_bluff[round_index] × guesser_count`
+- Score broadcast immediately (`phase.score_delta`)
+- Skipped lies (0 guesses): not shown at all
+
+### REVEAL_TRUTH
+- Broadcast: correct answer, who guessed correctly (`phase.reveal_truth`)
+- Score awarded: `points_correct[round_index]` per correct guesser
+- Also show reaction totals on each lie during this phase
+
+### SCOREBOARD_RECAP
+- Full leaderboard broadcast (`phase.scoreboard`)
+- Auto-advances to next question, next round, or post-game
+
+### POST_GAME_AWARDS
+- Computed from `LieReaction` aggregate:
+  - "Most Hilarious Liar" — most 😂 reactions total
+  - "Most Beloved Lie" — most ❤️ reactions on a single lie
+  - etc. (extensible)
+- Broadcast as `phase.awards`
+- Then FINISHED → GameRun deleted, all session game data wiped
+
+---
+
+## Fup og Fakta — Models
+
+**Existing (keep):** `Category`, `Question`, `RoundQuestion`, `LieAnswer`, `Guess`
+
+**Remove:** `ScoreEvent` (no audit trail needed — game state is ephemeral)
+
+**New:**
+```python
+class LieReaction(models.Model):
+    lie      = ForeignKey(LieAnswer, on_delete=CASCADE)
+    player   = ForeignKey(Player, on_delete=CASCADE)
+    reaction = CharField(max_length=20)  # "laugh", "heart", "fire", etc.
+    created_at = auto_now_add
+    class Meta:
+        unique_together = [("lie", "player", "reaction")]
+```
+
+**Modify `RoundQuestion`:**
+- Add `reveal_order` (PositiveIntegerField, nullable) — set when GUESS_PHASE ends, determines reveal sequence
+
+---
+
+## Pause / Resume
+
+- **Pause:** compute `remaining = phase_deadline - now`, store in `paused_remaining_seconds`, set `is_paused=True`, revoke Celery task by `celery_task_id`
+- **Resume:** set `phase_deadline = now + paused_remaining_seconds`, schedule new Celery task, clear pause fields
+- Stale task guard: every Celery task checks `expected_state == run.current_state` before firing
+
+---
+
+## Host Controls (Session Owner Only)
+
+| Action | Effect |
+|--------|--------|
+| Play   | Starts game from LOBBY, or resumes from paused |
+| Pause  | Freezes current phase timer, broadcasts `phase.paused` |
+| Exit   | Ends game immediately, deletes GameRun + all game data |
+
+Cannot skip. Cannot manually advance phases.
+
+---
+
+## WebSocket Event Reference
+
+| Event | Triggered by | Payload |
+|-------|-------------|---------|
+| `phase.lie_started` | LIE_PHASE start | question prompt, deadline, round info |
+| `phase.lie_progress` | Each lie submitted | n_submitted / n_players (no names) |
+| `phase.guess_started` | GUESS_PHASE start | mixed answers, deadline |
+| `phase.reveal_lie` | REVEAL_LIE_{n} | lie text, author, guessers, score delta |
+| `phase.reveal_truth` | REVEAL_TRUTH | correct answer, correct guessers, score delta |
+| `phase.scoreboard` | SCOREBOARD_RECAP | full leaderboard |
+| `phase.awards` | POST_GAME_AWARDS | award winners |
+| `phase.paused` | Pause | remaining_seconds |
+| `phase.resumed` | Resume | new deadline |
+| `phase.game_over` | FINISHED | final leaderboard |
+
+---
+
+## Data Lifecycle
+
+All game session data (`GameRun`, `RoundQuestion`, `LieAnswer`, `Guess`, `LieReaction`, `Player`) is **deleted when host exits or game reaches FINISHED**. `GameSession` row is kept (with status=FINISHED) for the session code uniqueness constraint. `Category` and `Question` content is permanent.
+
+---
+
+## Not In Scope (This Implementation)
+
+- TTS / read-aloud (Fase 4, deferred)
+- Reconnect recovery after server restart (game is gone if server dies)
+- Spectator/viewer mode (post-MVP)
+- Rate limiting on endpoints (backlog)
+- Bulk question import (Fase 5)

docs/spa-cutover-flag.md

@@ -0,0 +1,99 @@
+# SPA cutover feature flag (`USE_SPA_UI`)
+
+## Formål
+`USE_SPA_UI` styrer om host/player UI routes serverer Angular SPA shell eller legacy Django templates.
+
+## Miljø-toggle (uden kodeændring)
+Sæt env var pr. miljø:
+
+- `USE_SPA_UI=true` -> `/lobby/ui/host` og `/lobby/ui/player` returnerer SPA shell
+- `USE_SPA_UI=false` (default) -> legacy template-flow bruges uændret
+
+Backward compatibility under cutover:
+- Hvis `USE_SPA_UI` ikke er sat, bruges `WPP_SPA_ENABLED` som fallback.
+
+## Static asset versioning/cache-busting (hardening)
+Formål: sikre at browser/proxy/CDN hurtigt henter ny SPA bundle i release-vinduet uden at kræve hard refresh.
+
+- `WPP_SPA_ASSET_BASE` peger fortsat på build-output (`/static/frontend/angular/browser`).
+- `WPP_SPA_ASSET_VERSION` injiceres i SPA shell URLs som query-param (`?v=<version>`).
+- Anbefalet værdi for `WPP_SPA_ASSET_VERSION`: release-tag eller kort commit SHA.
+- Ved rollback sættes `WPP_SPA_ASSET_VERSION` til den tidligere kendte stabile release-værdi.
+
+Eksempel (staging/prod env):
+
+```env
+USE_SPA_UI=true
+WPP_SPA_ASSET_BASE=/static/frontend/angular/browser
+WPP_SPA_ASSET_VERSION=rel-2026-03-01-bb82357
+```
+
+## Staging rollout-checkliste (`USE_SPA_UI`)
+1. **Baseline (flag OFF)**
+   - Bekræft at staging kører med `USE_SPA_UI=false`.
+   - Kør gameplay smoke på legacy routes (`/lobby/ui/host` + `/lobby/ui/player`).
+2. **Smoke-gate før aktivering (skal være grøn)**
+   - Cutover route sanity = PASS for både OFF og ON checks.
+   - Full gameplay round (join/start/round/scoreboard) = PASS.
+   - Next-round/final leaderboard sanity = PASS.
+   - Ingen nye blocker-regressioner i host/player kerneflow.
+3. **Kontrolleret aktivering i staging**
+   - Sæt `USE_SPA_UI=true` i staging miljøet.
+   - Kør smoke-flow igen med SPA-route-verifikation.
+4. **Post-cutover dokumentation**
+   - Log evidens med commit/head SHA, UTC timestamp og gate-status.
+
+## Rollback playbook (`USE_SPA_UI`) — mål: <10 min
+Rollback til legacy (`USE_SPA_UI=false`) udføres straks hvis et checkpoint fejler:
+- Forkert route/shell for valgt flag i cutover route sanity.
+- Gameplay smoke kan ikke gennemføres til scoreboard/final leaderboard.
+- Kritisk regression i host/player flow under smoke.
+
+Trin-for-trin:
+1. Sæt `USE_SPA_UI=false` i deploy-env.
+2. Sæt `WPP_SPA_ASSET_VERSION` til sidste stabile release-token.
+3. Deploy/reload app-processer.
+4. Verificér legacy routes: `/lobby/ui/host` + `/lobby/ui/player`.
+5. Kør hurtig smoke sanity (join/start/scoreboard path).
+6. Log UTC tid, trigger, release-token og resultat i smoke artifact.
+
+Target: rollback + sanity-verifikation inden for 10 minutter.
+
+## React fallback trigger-kriterier (kun delivery-blocking)
+Formål: React fallback må kun bruges som kortvarig leverings-sikring, når release ellers er blokeret.
+
+### Hvornår fallback er tilladt
+Alle punkter skal være opfyldt:
+1. **Delivery-blocking fejl i Angular SPA**
+   - Host/player kerneflow kan ikke leveres i release-vinduet (fx login/join/start/round/scoreboard stopper).
+2. **Ingen hurtig Angular-fix inden for release-vinduet**
+   - Teamet har vurderet at patch + verificering ikke kan nås sikkert i tide.
+3. **Rollback alene løser ikke leveringsbehovet**
+   - `USE_SPA_UI=false` (legacy) er enten utilstrækkelig for den konkrete leverance eller allerede verificeret som ikke tilstrækkelig.
+4. **Beslutning er eksplicit logget**
+   - Trigger, impact, UTC-tid, ansvarlig, issue/incident-reference og plan for tilbagevenden til Angular er dokumenteret i release/smoke artifact.
+
+### Scope-limits for fallback
+- Fallback omfatter kun **delivery-blocking host/player-paths**.
+- Ingen nye features, UX-forbedringer eller ikke-kritiske ændringer må bundtes ind i fallback.
+- Fallback er **midlertidig** og gælder kun for aktiv incident/release-vindue.
+- Når blocker er fjernet, skal miljøet tilbage på standard cutover-spor (Angular + `USE_SPA_UI` styring).
+
+### Ikke tilladt
+- Proaktiv fallback "for en sikkerheds skyld" uden aktiv blocker.
+- Brug af fallback til at omgå normale kvalitetsgates eller testkrav.
+- Langvarig drift i fallback-mode uden dokumenteret blocker og opfølgningsplan.
+
+## Verifikation
+- Flag OFF: `UiScreenTests.test_legacy_templates_are_used_when_spa_flag_is_off`
+- Flag ON (host): `UiScreenTests.test_host_screen_can_render_angular_shell_when_feature_flag_enabled`
+- Flag ON (host deep-link): `UiScreenTests.test_host_screen_deeplink_preserves_spa_path_when_feature_flag_enabled`
+- Flag ON (player): `UiScreenTests.test_player_screen_can_render_angular_shell_when_feature_flag_enabled`
+- Smoke-checkliste for cutover paths: `docs/STAGING_GAMEPLAY_SMOKE_ARTIFACT.md` + `docs/UI_SMOKE.md`
+
+
+## MVP audio policy guardrail (telefon-klient)
+- Telefon-/player-klienten må ikke starte lydafspilning lokalt i MVP (`primary-device only`).
+- Policy er bundet til capability-flaget `frontend.capabilities.client_has_no_audio_output=true` i `shared/i18n/lobby.json`.
+- Brugeradvarsel i player UI leveres via i18n key: `frontend.ui.player.audio_policy_notice`.
+- Acceptance-spec er dækket i Angular tests (`player-shell.component.spec.ts`), inkl. at init-path ikke kalder original media `play`.

frontend/.gitignore

@@ -0,0 +1 @@
+node_modules/

frontend/README.md

@@ -0,0 +1,12 @@
+# Frontend API client baseline
+
+Dette er baseline-klientlaget for SPA-sporet.
+
+## Kører checks lokalt
+
+```bash
+cd frontend
+npm install
+npm test
+npm run build
+```

frontend/angular/.gitignore

@@ -0,0 +1,3 @@
+node_modules/
+dist/
+.angular/

frontend/angular/angular.json

@@ -0,0 +1,36 @@
+{
+  "$schema": "./node_modules/@angular/cli/lib/config/schema.json",
+  "version": 1,
+  "projects": {
+    "wpp-angular-shell": {
+      "projectType": "application",
+      "root": "",
+      "sourceRoot": "src",
+      "prefix": "app",
+      "architect": {
+        "build": {
+          "builder": "@angular/build:application",
+          "options": {
+            "outputPath": "dist/wpp-angular-shell",
+            "index": "src/index.html",
+            "browser": "src/main.ts",
+            "polyfills": ["zone.js"],
+            "tsConfig": "tsconfig.app.json",
+            "assets": [],
+            "styles": ["src/styles.css"],
+            "outputHashing": "none"
+          }
+        },
+        "serve": {
+          "builder": "@angular/build:dev-server",
+          "options": {
+            "buildTarget": "wpp-angular-shell:build"
+          }
+        }
+      }
+    }
+  },
+  "cli": {
+    "analytics": false
+  }
+}

frontend/angular/package.json

@@ -0,0 +1,28 @@
+{
+  "name": "wpp-angular-shell",
+  "version": "0.0.0",
+  "private": true,
+  "scripts": {
+    "start": "ng serve",
+    "build": "ng build",
+    "test": "vitest run"
+  },
+  "dependencies": {
+    "@angular/common": "^19.2.0",
+    "@angular/compiler": "^19.2.0",
+    "@angular/core": "^19.2.0",
+    "@angular/forms": "^19.2.0",
+    "@angular/platform-browser": "^19.2.0",
+    "@angular/router": "^19.2.0",
+    "rxjs": "~7.8.0",
+    "tslib": "^2.3.0",
+    "zone.js": "~0.15.0"
+  },
+  "devDependencies": {
+    "@angular/build": "^19.2.0",
+    "@angular/cli": "^19.2.0",
+    "@angular/compiler-cli": "^19.2.0",
+    "typescript": "~5.7.2",
+    "vitest": "^2.1.9"
+  }
+}

frontend/angular/src/app/api-contract-smoke.spec.ts

@@ -0,0 +1,273 @@
+import { describe, expect, it, vi } from 'vitest';
+
+import { createAngularApiClient, type AngularHttpClientLike } from '../../../src/api/angular-client';
+
+describe('SPA Angular API contract smoke (host/player foundation)', () => {
+  it('smoke-checks canonical host/player endpoint contracts', async () => {
+    const get = vi.fn<AngularHttpClientLike['get']>(async <T>(url: string) => {
+      if (url === '/lobby/sessions/ABCD12') {
+        return {
+          session: { code: 'ABCD12', status: 'lobby', host_id: 1, current_round: 1, players_count: 2 },
+          players: [
+            { id: 2, nickname: 'Maja', score: 0, is_connected: true },
+            { id: 3, nickname: 'Bo', score: 0, is_connected: true }
+          ],
+          round_question: {
+            id: 77,
+            round_number: 1,
+            prompt: 'Q?',
+            shown_at: '2026-03-01T18:00:00Z',
+            answers: [{ text: 'A' }, { text: 'B' }]
+          },
+          reveal: {
+            round_question_id: 77,
+            round_number: 1,
+            prompt: 'Q?',
+            correct_answer: 'A',
+            lies: [{ player_id: 2, nickname: 'Maja', text: 'B', created_at: '2026-03-01T18:00:05Z' }],
+            guesses: [
+              {
+                player_id: 3,
+                nickname: 'Bo',
+                selected_text: 'B',
+                is_correct: false,
+                fooled_player_id: 2,
+                fooled_player_nickname: 'Maja',
+                created_at: '2026-03-01T18:00:15Z'
+              }
+            ]
+          },
+          phase_view_model: {
+            status: 'lobby',
+            round_number: 1,
+            players_count: 2,
+            constraints: {
+              min_players_to_start: 2,
+              max_players_mvp: 8,
+              min_players_reached: true,
+              max_players_allowed: true
+            },
+            host: {
+              can_start_round: true,
+              can_show_question: false,
+              can_mix_answers: false,
+              can_calculate_scores: false,
+              can_reveal_scoreboard: false,
+              can_start_next_round: false,
+              can_finish_game: false
+            },
+            player: {
+              can_join: true,
+              can_submit_lie: false,
+              can_submit_guess: false,
+              can_view_final_result: false
+            }
+          }
+        } as T;
+      }
+
+      if (url === '/lobby/sessions/ABCD12/scoreboard') {
+        return {
+          session: { code: 'ABCD12', status: 'scoreboard', current_round: 1 },
+          leaderboard: [
+            { id: 9, nickname: 'Maja', score: 200 },
+            { id: 10, nickname: 'Bo', score: 150 }
+          ]
+        } as T;
+      }
+
+      throw { status: 404, error: { error: 'Not found' } };
+    });
+
+    const post = vi.fn<AngularHttpClientLike['post']>(async <T>(url: string, body: unknown) => {
+      if (url === '/lobby/sessions/join') {
+        expect(body).toEqual({ code: 'ABCD12', nickname: 'Maja' });
+        return {
+          player: { id: 9, nickname: 'Maja', session_token: 'session-token-1', score: 0 },
+          session: { code: 'ABCD12', status: 'lobby' }
+        } as T;
+      }
+
+      if (url === '/lobby/sessions/ABCD12/rounds/start') {
+        expect(body).toEqual({ category_slug: 'history' });
+        return {
+          session: { code: 'ABCD12', status: 'lie', current_round: 1 },
+          round: { number: 1, category: { slug: 'history', name: 'History' } }
+        } as T;
+      }
+
+      if (url === '/lobby/sessions/ABCD12/questions/show') {
+        expect(body).toEqual({});
+        return {
+          round_question: {
+            id: 77,
+            prompt: 'Q?',
+            round_number: 1,
+            shown_at: '2026-03-01T18:00:00Z',
+            lie_deadline_at: '2026-03-01T18:00:30Z'
+          },
+          config: { lie_seconds: 30 }
+        } as T;
+      }
+
+      if (url === '/lobby/sessions/ABCD12/questions/77/answers/mix') {
+        expect(body).toEqual({});
+        return {
+          session: { code: 'ABCD12', status: 'guess', current_round: 1 },
+          round_question: { id: 77, round_number: 1 },
+          answers: [{ text: 'A' }, { text: 'B' }]
+        } as T;
+      }
+
+      if (url === '/lobby/sessions/ABCD12/questions/77/scores/calculate') {
+        expect(body).toEqual({});
+        return {
+          session: { code: 'ABCD12', status: 'reveal', current_round: 1 },
+          round_question: { id: 77, round_number: 1 },
+          events_created: 2,
+          reveal: {
+            round_question_id: 77,
+            correct_answer: 'A',
+            lies: [],
+            guesses: []
+          },
+          leaderboard: [
+            { id: 9, nickname: 'Maja', score: 200 },
+            { id: 10, nickname: 'Bo', score: 150 }
+          ]
+        } as T;
+      }
+
+      if (url === '/lobby/sessions/ABCD12/rounds/next') {
+        expect(body).toEqual({});
+        return { session: { code: 'ABCD12', status: 'lie', current_round: 2 } } as T;
+      }
+
+      if (url === '/lobby/sessions/ABCD12/finish') {
+        expect(body).toEqual({});
+        return {
+          session: { code: 'ABCD12', status: 'finished', current_round: 2 },
+          winner: { id: 9, nickname: 'Maja', score: 250 },
+          leaderboard: [
+            { id: 9, nickname: 'Maja', score: 250 },
+            { id: 10, nickname: 'Bo', score: 150 }
+          ]
+        } as T;
+      }
+
+      if (url === '/lobby/sessions/ABCD12/questions/77/lies/submit') {
+        expect(body).toEqual({ player_id: 9, session_token: 'session-token-1', text: 'my lie' });
+        return {
+          lie: {
+            id: 501,
+            player_id: 9,
+            round_question_id: 77,
+            text: 'my lie',
+            created_at: '2026-03-01T18:00:05Z'
+          },
+          window: { lie_deadline_at: '2026-03-01T18:00:30Z' }
+        } as T;
+      }
+
+      if (url === '/lobby/sessions/ABCD12/questions/77/guesses/submit') {
+        expect(body).toEqual({ player_id: 9, session_token: 'session-token-1', selected_text: 'B' });
+        return {
+          guess: {
+            id: 601,
+            player_id: 9,
+            round_question_id: 77,
+            selected_text: 'B',
+            is_correct: false,
+            fooled_player_id: null,
+            created_at: '2026-03-01T18:00:15Z'
+          },
+          window: { guess_deadline_at: '2026-03-01T18:01:00Z' }
+        } as T;
+      }
+
+      throw { status: 404, error: { error: 'Not found' } };
+    });
+
+    const client = createAngularApiClient({ get, post } as AngularHttpClientLike);
+
+    const session = await client.getSession(' abcd12 ');
+    expect(session.ok).toBe(true);
+    if (session.ok) {
+      expect(session.data.session.code).toBe('ABCD12');
+      expect(session.data.phase_view_model.host.can_start_next_round).toBe(false);
+      expect(session.data.phase_view_model.player.can_submit_guess).toBe(false);
+      expect(session.data.reveal?.correct_answer).toBe('A');
+      expect(session.data.reveal?.guesses[0].fooled_player_nickname).toBe('Maja');
+    }
+
+    expect((await client.joinSession({ code: ' abcd12 ', nickname: ' Maja ' })).ok).toBe(true);
+    expect((await client.startRound(' abcd12 ', { category_slug: 'history' })).ok).toBe(true);
+    expect((await client.showQuestion(' abcd12 ')).ok).toBe(true);
+    expect((await client.mixAnswers(' abcd12 ', 77)).ok).toBe(true);
+    expect((await client.calculateScores(' abcd12 ', 77)).ok).toBe(true);
+    expect((await client.getScoreboard(' abcd12 ')).ok).toBe(true);
+    expect((await client.startNextRound(' abcd12 ')).ok).toBe(true);
+    expect((await client.finishGame(' abcd12 ')).ok).toBe(true);
+    expect(
+      (
+        await client.submitLie(' abcd12 ', 77, {
+          player_id: 9,
+          session_token: 'session-token-1',
+          text: 'my lie'
+        })
+      ).ok
+    ).toBe(true);
+    expect(
+      (
+        await client.submitGuess(' abcd12 ', 77, {
+          player_id: 9,
+          session_token: 'session-token-1',
+          selected_text: 'B'
+        })
+      ).ok
+    ).toBe(true);
+
+    expect(get).toHaveBeenNthCalledWith(1, '/lobby/sessions/ABCD12', { withCredentials: true });
+    expect(get).toHaveBeenNthCalledWith(2, '/lobby/sessions/ABCD12/scoreboard', { withCredentials: true });
+
+    expect(post).toHaveBeenNthCalledWith(
+      1,
+      '/lobby/sessions/join',
+      { code: 'ABCD12', nickname: 'Maja' },
+      { withCredentials: true }
+    );
+    expect(post).toHaveBeenNthCalledWith(
+      2,
+      '/lobby/sessions/ABCD12/rounds/start',
+      { category_slug: 'history' },
+      { withCredentials: true }
+    );
+    expect(post).toHaveBeenNthCalledWith(3, '/lobby/sessions/ABCD12/questions/show', {}, { withCredentials: true });
+    expect(post).toHaveBeenNthCalledWith(
+      4,
+      '/lobby/sessions/ABCD12/questions/77/answers/mix',
+      {},
+      { withCredentials: true }
+    );
+    expect(post).toHaveBeenNthCalledWith(
+      5,
+      '/lobby/sessions/ABCD12/questions/77/scores/calculate',
+      {},
+      { withCredentials: true }
+    );
+    expect(post).toHaveBeenNthCalledWith(6, '/lobby/sessions/ABCD12/rounds/next', {}, { withCredentials: true });
+    expect(post).toHaveBeenNthCalledWith(7, '/lobby/sessions/ABCD12/finish', {}, { withCredentials: true });
+    expect(post).toHaveBeenNthCalledWith(
+      8,
+      '/lobby/sessions/ABCD12/questions/77/lies/submit',
+      { player_id: 9, session_token: 'session-token-1', text: 'my lie' },
+      { withCredentials: true }
+    );
+    expect(post).toHaveBeenNthCalledWith(
+      9,
+      '/lobby/sessions/ABCD12/questions/77/guesses/submit',
+      { player_id: 9, session_token: 'session-token-1', selected_text: 'B' },
+      { withCredentials: true }
+    );
+  });
+});

frontend/angular/src/app/app.component.css

@@ -0,0 +1,5 @@
+.shell { font-family: Arial, sans-serif; margin: 1rem; }
+.shell__header { display: flex; flex-wrap: wrap; gap: 0.75rem; justify-content: space-between; align-items: center; border-bottom: 1px solid #ddd; padding-bottom: 0.75rem; }
+.shell__header nav { display: flex; gap: 0.75rem; }
+.shell__content { margin-top: 1rem; }
+.locale-picker { display: inline-flex; align-items: center; gap: 0.4rem; font-size: 0.95rem; }

frontend/angular/src/app/app.component.html

@@ -0,0 +1,20 @@
+<main class="shell">
+  <header class="shell__header">
+    <h1>{{ copy('app.title') }}</h1>
+    <nav>
+      <a routerLink="/host">{{ copy('app.host_nav') }}</a>
+      <a routerLink="/player">{{ copy('app.player_nav') }}</a>
+    </nav>
+    <label class="locale-picker">
+      {{ copy('app.language_label') }}
+      <select [ngModel]="locale" (ngModelChange)="setLocale($event)">
+        <option value="en">English</option>
+        <option value="da">Dansk</option>
+      </select>
+    </label>
+  </header>
+
+  <section class="shell__content" [attr.data-wpp-locale]="locale">
+    <router-outlet></router-outlet>
+  </section>
+</main>

frontend/angular/src/app/app.component.ts

@@ -0,0 +1,33 @@
+import { Component, inject } from '@angular/core';
+import { FormsModule } from '@angular/forms';
+import { Router, RouterLink, RouterOutlet } from '@angular/router';
+
+import { resolvePreferredLocale, setPreferredLocale, t } from './lobby-i18n';
+
+@Component({
+  selector: 'app-root',
+  standalone: true,
+  imports: [RouterOutlet, RouterLink, FormsModule],
+  templateUrl: './app.component.html',
+  styleUrl: './app.component.css',
+})
+export class AppComponent {
+  private readonly router = inject(Router);
+
+  locale = resolvePreferredLocale();
+
+  constructor() {
+    const shellRoute = document.body.dataset['wppShellRoute'];
+    if (shellRoute?.startsWith('/host') || shellRoute?.startsWith('/player')) {
+      void this.router.navigateByUrl(shellRoute);
+    }
+  }
+
+  copy(key: string): string {
+    return t(key, this.locale);
+  }
+
+  setLocale(locale: string): void {
+    this.locale = setPreferredLocale(locale);
+  }
+}

frontend/angular/src/app/app.config.ts

@@ -0,0 +1,15 @@
+import { ApplicationConfig } from '@angular/core';
+import { provideRouter, withHashLocation } from '@angular/router';
+
+import { routes } from './app.routes';
+import { createWppApiClient, WPP_API_CLIENT } from './wpp-api-client';
+
+export const appConfig: ApplicationConfig = {
+  providers: [
+    provideRouter(routes, withHashLocation()),
+    {
+      provide: WPP_API_CLIENT,
+      useFactory: () => createWppApiClient(),
+    },
+  ],
+};

frontend/angular/src/app/app.routes.ts

@@ -0,0 +1,49 @@
+import { Routes } from '@angular/router';
+
+import {
+  hostRouteContextResolver,
+  hostRouteGuard,
+  playerRouteContextResolver,
+  playerRouteGuard,
+} from './session-route-context';
+
+export const routes: Routes = [
+  {
+    path: 'host',
+    resolve: { routeContext: hostRouteContextResolver },
+    canActivate: [hostRouteGuard],
+    loadComponent: () => import('./features/host/host-shell.component').then((m) => m.HostShellComponent),
+  },
+  {
+    path: 'host/:phase',
+    resolve: { routeContext: hostRouteContextResolver },
+    canActivate: [hostRouteGuard],
+    loadComponent: () => import('./features/host/host-shell.component').then((m) => m.HostShellComponent),
+  },
+  {
+    path: 'host/:phase/:context',
+    resolve: { routeContext: hostRouteContextResolver },
+    canActivate: [hostRouteGuard],
+    loadComponent: () => import('./features/host/host-shell.component').then((m) => m.HostShellComponent),
+  },
+  {
+    path: 'player',
+    resolve: { routeContext: playerRouteContextResolver },
+    canActivate: [playerRouteGuard],
+    loadComponent: () => import('./features/player/player-shell.component').then((m) => m.PlayerShellComponent),
+  },
+  {
+    path: 'player/:phase',
+    resolve: { routeContext: playerRouteContextResolver },
+    canActivate: [playerRouteGuard],
+    loadComponent: () => import('./features/player/player-shell.component').then((m) => m.PlayerShellComponent),
+  },
+  {
+    path: 'player/:phase/:context',
+    resolve: { routeContext: playerRouteContextResolver },
+    canActivate: [playerRouteGuard],
+    loadComponent: () => import('./features/player/player-shell.component').then((m) => m.PlayerShellComponent),
+  },
+  { path: '', pathMatch: 'full', redirectTo: 'player' },
+  { path: '**', redirectTo: 'player' },
+];

frontend/angular/src/app/features/host/host-shell.component.spec.ts

@@ -0,0 +1,455 @@
+import { afterEach, describe, expect, it, vi } from 'vitest';
+
+import { HostShellComponent } from './host-shell.component';
+
+type FetchMock = ReturnType<typeof vi.fn>;
+
+type FetchRouteHandler = (input: RequestInfo | URL, init?: RequestInit) => Response | Promise<Response>;
+
+function jsonResponse(status: number, body: unknown) {
+  return {
+    ok: status >= 200 && status < 300,
+    status,
+    json: vi.fn().mockResolvedValue(body),
+  } as unknown as Response;
+}
+
+function createFetchRouteMock(handler: FetchRouteHandler): FetchMock {
+  return vi.fn((input: RequestInfo | URL, init?: RequestInit) => Promise.resolve(handler(input, init)));
+}
+
+function sessionDetailPayload(
+  status: string,
+  options?: {
+    currentPhase?: string;
+    roundQuestionId?: number | null;
+    reveal?: {
+      correct_answer: string;
+      prompt?: string;
+      lies?: Array<{ player_id: number; nickname: string; text: string; created_at?: string }>;
+      guesses?: Array<{
+        player_id: number;
+        nickname: string;
+        selected_text: string;
+        is_correct: boolean;
+        fooled_player_id: number | null;
+        fooled_player_nickname?: string;
+        created_at?: string;
+      }>;
+    } | null;
+  }
+) {
+  const roundQuestionId = options?.roundQuestionId ?? 41;
+
+  return {
+    session: {
+      code: 'ABCD12',
+      status,
+      host_id: 1,
+      current_round: status === 'lobby' ? 2 : 1,
+      players_count: 2,
+    },
+    round_question:
+      roundQuestionId === null
+        ? null
+        : {
+            id: roundQuestionId,
+            round_number: 1,
+            prompt: 'Q?',
+            shown_at: '2026-01-01T00:00:00Z',
+            answers: [],
+          },
+    players: [
+      { id: 1, nickname: 'Host', score: 0, is_connected: true },
+      { id: 2, nickname: 'Mads', score: 120, is_connected: true },
+    ],
+    reveal:
+      options?.reveal === undefined || options?.reveal === null
+        ? null
+        : {
+            round_question_id: roundQuestionId,
+            round_number: 1,
+            prompt: options.reveal.prompt ?? 'Q?',
+            correct_answer: options.reveal.correct_answer,
+            lies: (options.reveal.lies ?? []).map((lie) => ({
+              ...lie,
+              created_at: lie.created_at ?? '2026-01-01T00:00:05Z',
+            })),
+            guesses: (options.reveal.guesses ?? []).map((guess) => ({
+              ...guess,
+              created_at: guess.created_at ?? '2026-01-01T00:00:10Z',
+            })),
+          },
+    phase_view_model: {
+      status,
+      current_phase: options?.currentPhase ?? status,
+      round_number: 1,
+      players_count: 2,
+      constraints: {
+        min_players_to_start: 2,
+        max_players_mvp: 8,
+        min_players_reached: true,
+        max_players_allowed: true,
+      },
+      readiness: {
+        question_ready: (options?.currentPhase ?? status) !== 'lobby',
+        scoreboard_ready: (options?.currentPhase ?? status) === 'reveal' || (options?.currentPhase ?? status) === 'scoreboard',
+      },
+      host: {
+        can_start_round: (options?.currentPhase ?? status) === 'lobby',
+        can_show_question: (options?.currentPhase ?? status) === 'lie',
+        can_mix_answers: (options?.currentPhase ?? status) === 'lie' || (options?.currentPhase ?? status) === 'guess',
+        can_calculate_scores: (options?.currentPhase ?? status) === 'guess',
+        can_reveal_scoreboard: (options?.currentPhase ?? status) === 'reveal',
+        can_start_next_round: (options?.currentPhase ?? status) === 'scoreboard',
+        can_finish_game: (options?.currentPhase ?? status) === 'scoreboard',
+      },
+      player: {
+        can_join: status === 'lobby',
+        can_submit_lie: status === 'lie',
+        can_submit_guess: status === 'guess',
+        can_view_final_result: status === 'finished',
+      },
+    },
+  };
+}
+
+describe('HostShellComponent gameplay wiring', () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it('runs startRound transition and refreshes session details', async () => {
+    const fetchMock: FetchMock = vi
+      .fn()
+      .mockResolvedValueOnce(
+        jsonResponse(201, {
+          session: { code: 'ABCD12', status: 'lie', current_round: 1 },
+          round: { number: 1, category: { slug: 'history', name: 'History' } },
+        })
+      )
+      .mockResolvedValueOnce(jsonResponse(200, sessionDetailPayload('lie')));
+
+    vi.stubGlobal('fetch', fetchMock);
+
+    const component = new HostShellComponent();
+    component.sessionCode = ' abcd12 ';
+    component.categorySlug = ' history ';
+
+    await component.startRound();
+
+    expect(fetchMock).toHaveBeenNthCalledWith(
+      1,
+      '/lobby/sessions/ABCD12/rounds/start',
+      expect.objectContaining({ method: 'POST', body: JSON.stringify({ category_slug: 'history' }) })
+    );
+    expect(fetchMock).toHaveBeenNthCalledWith(2, '/lobby/sessions/ABCD12', expect.objectContaining({ method: 'GET' }));
+    expect(component.session?.session.status).toBe('lie');
+    expect(component.roundQuestionId).toBe('41');
+    expect(component.loading).toBe(false);
+  });
+
+  it('hydrates canonical reveal payload in reveal phase', async () => {
+    const fetchMock: FetchMock = vi.fn().mockResolvedValue(
+      jsonResponse(
+        200,
+        sessionDetailPayload('reveal', {
+          roundQuestionId: 77,
+          reveal: {
+            correct_answer: 'Mercury',
+            lies: [{ player_id: 2, nickname: 'Mads', text: 'Venus' }],
+            guesses: [
+              {
+                player_id: 3,
+                nickname: 'Luna',
+                selected_text: 'Venus',
+                is_correct: false,
+                fooled_player_id: 2,
+                fooled_player_nickname: 'Mads',
+              },
+            ],
+          },
+        })
+      )
+    );
+
+    vi.stubGlobal('fetch', fetchMock);
+
+    const component = new HostShellComponent();
+    component.sessionCode = 'ABCD12';
+
+    await component.refreshSession();
+
+    expect(component.session?.reveal?.correct_answer).toBe('Mercury');
+    expect(component.session?.reveal?.lies[0]).toMatchObject({ player_id: 2, nickname: 'Mads', text: 'Venus' });
+    expect(component.session?.reveal?.guesses[0]).toMatchObject({
+      player_id: 3,
+      nickname: 'Luna',
+      selected_text: 'Venus',
+      fooled_player_id: 2,
+      fooled_player_nickname: 'Mads',
+    });
+  });
+
+  it('wires showQuestion, mixAnswers and calculateScores with canonical phase gating', async () => {
+    let refreshCount = 0;
+    const fetchMock = createFetchRouteMock((input, init) => {
+      const url = String(input);
+      const method = init?.method ?? 'GET';
+
+      if (method === 'POST' && url === '/lobby/sessions/ABCD12/questions/show') {
+        return jsonResponse(200, { session: { code: 'ABCD12', status: 'lie', current_round: 2 } });
+      }
+      if (method === 'POST' && url === '/lobby/sessions/ABCD12/questions/99/answers/mix') {
+        return jsonResponse(200, { session: { code: 'ABCD12', status: 'guess', current_round: 2 } });
+      }
+      if (method === 'POST' && url === '/lobby/sessions/ABCD12/questions/77/scores/calculate') {
+        return jsonResponse(200, { session: { code: 'ABCD12', status: 'reveal', current_round: 2 } });
+      }
+      if (method === 'GET' && url === '/lobby/sessions/ABCD12') {
+        refreshCount += 1;
+        if (refreshCount === 1) {
+          return jsonResponse(200, sessionDetailPayload('lie', { roundQuestionId: 99 }));
+        }
+        if (refreshCount === 2) {
+          return jsonResponse(200, sessionDetailPayload('guess', { roundQuestionId: 77 }));
+        }
+        return jsonResponse(200, sessionDetailPayload('reveal', { roundQuestionId: 77 }));
+      }
+
+      throw new Error(`Unhandled fetch in test: ${method} ${url}`);
+    });
+
+    vi.stubGlobal('fetch', fetchMock);
+
+    const component = new HostShellComponent();
+    component.sessionCode = ' abcd12 ';
+    component.roundQuestionId = ' 77 ';
+
+    component.session = sessionDetailPayload('lie', { roundQuestionId: null }) as any;
+    await component.showQuestion();
+    expect(component.session?.session.status).toBe('lie');
+    expect(component.roundQuestionId).toBe('99');
+
+    component.session = sessionDetailPayload('guess', { roundQuestionId: 77 }) as any;
+    await component.mixAnswers();
+    expect(component.session?.session.status).toBe('guess');
+
+    await component.calculateScores();
+
+    expect(component.session?.session.status).toBe('reveal');
+    expect(component.error).toBe('');
+    expect(component.loading).toBe(false);
+    expect(fetchMock).toHaveBeenCalledTimes(6);
+  });
+
+  it('runs next-round transition without reload and clears scoreboard payload', async () => {
+    const fetchMock = createFetchRouteMock((input, init) => {
+      const url = String(input);
+      const method = init?.method ?? 'GET';
+
+      if (method === 'POST' && url === '/lobby/sessions/ABCD12/rounds/next') {
+        return jsonResponse(200, { session: { code: 'ABCD12', status: 'lie', current_round: 2 } });
+      }
+      if (method === 'GET' && url === '/lobby/sessions/ABCD12') {
+        return jsonResponse(200, sessionDetailPayload('lie', { roundQuestionId: 99 }));
+      }
+
+      throw new Error(`Unhandled fetch in test: ${method} ${url}`);
+    });
+
+    vi.stubGlobal('fetch', fetchMock);
+
+    const component = new HostShellComponent();
+    component.sessionCode = ' abcd12 ';
+    component.scoreboardPayload = '{"leaderboard":[]}';
+    component.finalLeaderboardPayload = '{"leaderboard":[{"nickname":"Old","score":1}]}' ;
+    component.finalLeaderboard = [{ id: 9, nickname: 'Old', score: 1 }];
+    component.session = sessionDetailPayload('scoreboard', { roundQuestionId: 77 }) as any;
+
+    await component.startNextRound();
+
+    expect(fetchMock).toHaveBeenNthCalledWith(
+      1,
+      '/lobby/sessions/ABCD12/rounds/next',
+      expect.objectContaining({ method: 'POST', body: JSON.stringify({}) })
+    );
+    expect(fetchMock).toHaveBeenNthCalledWith(2, '/lobby/sessions/ABCD12', expect.objectContaining({ method: 'GET' }));
+    expect(component.session?.session.status).toBe('lie');
+    expect(component.roundQuestionId).toBe('99');
+    expect(component.finalLeaderboardPayload).toBe('');
+    expect(component.finalLeaderboard).toEqual([]);
+    expect(component.nextRoundError).toBe('');
+  });
+
+  it('captures finish-game failure for retry and stores final leaderboard on success', async () => {
+    const fetchMock: FetchMock = vi
+      .fn()
+      .mockResolvedValueOnce(jsonResponse(503, { error: 'Final leaderboard timeout' }))
+      .mockResolvedValueOnce(
+        jsonResponse(200, {
+          session: { code: 'ABCD12', status: 'finished', current_round: 2 },
+          winner: { id: 1, nickname: 'Luna', score: 320 },
+          leaderboard: [
+            { id: 2, nickname: 'Mads', score: 120 },
+            { id: 1, nickname: 'Luna', score: 320 },
+          ],
+        })
+      )
+      .mockResolvedValueOnce(jsonResponse(200, sessionDetailPayload('finished', { roundQuestionId: null })));
+
+    vi.stubGlobal('fetch', fetchMock);
+
+    const component = new HostShellComponent();
+    component.sessionCode = 'ABCD12';
+    component.session = sessionDetailPayload('scoreboard', { roundQuestionId: 77 }) as any;
+
+    await component.finishGame();
+    expect(component.finishError).toContain('Finish game failed: Final leaderboard timeout');
+
+    await component.finishGame();
+
+    expect(fetchMock).toHaveBeenNthCalledWith(
+      2,
+      '/lobby/sessions/ABCD12/finish',
+      expect.objectContaining({ method: 'POST', body: JSON.stringify({}) })
+    );
+    expect(component.finishError).toBe('');
+    expect(component.finalLeaderboardPayload).toContain('"status": "finished"');
+    expect(component.finalWinner?.nickname).toBe('Luna');
+    expect(component.finalLeaderboard.map((entry) => entry.nickname)).toEqual(['Luna', 'Mads']);
+  });
+
+  it('guards next-round and finish actions when session code is missing', async () => {
+    const fetchMock: FetchMock = vi.fn();
+    vi.stubGlobal('fetch', fetchMock);
+
+    const component = new HostShellComponent();
+    component.sessionCode = '   ';
+    component.session = sessionDetailPayload('scoreboard', { roundQuestionId: 77 }) as any;
+
+    await component.startNextRound();
+    await component.finishGame();
+
+    expect(fetchMock).not.toHaveBeenCalled();
+    expect(component.nextRoundError).toContain('Session code is required');
+    expect(component.finishError).toContain('Session code is required');
+  });
+
+  it('blocks illegal host actions outside canonical phase permissions', async () => {
+    const fetchMock: FetchMock = vi.fn();
+    vi.stubGlobal('fetch', fetchMock);
+
+    const component = new HostShellComponent();
+    component.sessionCode = 'ABCD12';
+    component.roundQuestionId = '77';
+
+    for (const status of ['guess', 'reveal', 'scoreboard'] as const) {
+      component.session = sessionDetailPayload(status, { roundQuestionId: 77 }) as any;
+      await component.showQuestion();
+    }
+
+    for (const status of ['lie', 'reveal', 'scoreboard'] as const) {
+      component.session = sessionDetailPayload(status, { roundQuestionId: 77 }) as any;
+      await component.calculateScores();
+    }
+
+    for (const status of ['lie', 'guess', 'scoreboard'] as const) {
+      component.session = sessionDetailPayload(status, { roundQuestionId: 77 }) as any;
+      await component.loadScoreboard();
+    }
+
+    for (const status of ['lie', 'guess', 'reveal'] as const) {
+      component.session = sessionDetailPayload(status, { roundQuestionId: 77 }) as any;
+      await component.startNextRound();
+      await component.finishGame();
+    }
+
+    component.session = sessionDetailPayload('guess', { roundQuestionId: 77 }) as any;
+    expect(component.canShowQuestion).toBe(false);
+
+    component.session = sessionDetailPayload('reveal', { roundQuestionId: 77 }) as any;
+    expect(component.canCalculateScores).toBe(false);
+    expect(component.canLoadScoreboard).toBe(true);
+    expect(component.canStartNextRound).toBe(false);
+    expect(component.canFinishGame).toBe(false);
+
+    component.session = sessionDetailPayload('scoreboard', { roundQuestionId: 77 }) as any;
+    expect(component.canLoadScoreboard).toBe(false);
+    expect(component.canStartNextRound).toBe(true);
+    expect(component.canFinishGame).toBe(true);
+    expect(fetchMock).not.toHaveBeenCalled();
+  });
+
+  it('prefers canonical current_phase for reveal panel and host routing when status lags behind', async () => {
+    const fetchMock: FetchMock = vi.fn().mockResolvedValue(
+      jsonResponse(200, sessionDetailPayload('reveal', { currentPhase: 'scoreboard', roundQuestionId: 77, reveal: { correct_answer: 'Mercury' } }))
+    );
+    vi.stubGlobal('fetch', fetchMock);
+
+    const replaceState = vi.fn();
+    vi.stubGlobal('window', {
+      location: { hash: '#/host/reveal/ABCD12' },
+      history: { state: null, replaceState },
+      sessionStorage: { getItem: vi.fn().mockReturnValue(null), setItem: vi.fn() },
+    });
+
+    const component = new HostShellComponent();
+    component.sessionCode = 'ABCD12';
+
+    await component.refreshSession();
+
+    expect(component.gameplayPhase).toBe('scoreboard');
+    expect(component.showRevealPanel).toBe(true);
+    expect(component.canLoadScoreboard).toBe(false);
+    expect(component.canStartNextRound).toBe(true);
+    expect(component.canFinishGame).toBe(true);
+    expect(replaceState).toHaveBeenCalledWith(null, '', '#/host/scoreboard/ABCD12');
+  });
+
+  it('syncs host hash-route with latest phase after refresh without page reload', async () => {
+    const fetchMock: FetchMock = vi.fn().mockResolvedValue(jsonResponse(200, sessionDetailPayload('guess', { roundQuestionId: 77 })));
+    vi.stubGlobal('fetch', fetchMock);
+
+    const replaceState = vi.fn();
+    vi.stubGlobal('window', {
+      location: { hash: '#/host/lobby/ABCD12' },
+      history: { state: null, replaceState },
+      sessionStorage: { getItem: vi.fn().mockReturnValue(null), setItem: vi.fn() },
+    });
+
+    const component = new HostShellComponent();
+    component.sessionCode = 'ABCD12';
+
+    await component.refreshSession();
+
+    expect(replaceState).toHaveBeenCalledWith(null, '', '#/host/guess/ABCD12');
+    expect(component.canStartRound).toBe(false);
+    expect(component.canStartNextRound).toBe(false);
+    expect(component.canFinishGame).toBe(false);
+  });
+
+  it('uses phase_view_model to keep host action surface bound to round boundaries only', async () => {
+    const component = new HostShellComponent();
+
+    expect(component.canStartRound).toBe(true);
+    expect(component.canStartNextRound).toBe(false);
+    expect(component.canFinishGame).toBe(false);
+
+    component.session = sessionDetailPayload('lie') as any;
+    expect(component.canStartRound).toBe(false);
+    expect(component.canShowQuestion).toBe(true);
+    expect(component.canStartNextRound).toBe(false);
+    expect(component.canFinishGame).toBe(false);
+
+    component.session = sessionDetailPayload('reveal') as any;
+    expect(component.canLoadScoreboard).toBe(true);
+    expect(component.canStartNextRound).toBe(false);
+    expect(component.canFinishGame).toBe(false);
+
+    component.session = sessionDetailPayload('scoreboard') as any;
+    expect(component.canLoadScoreboard).toBe(false);
+    expect(component.canStartNextRound).toBe(true);
+    expect(component.canFinishGame).toBe(true);
+  });
+});

frontend/angular/src/app/features/host/host-shell.component.ts

@@ -0,0 +1,396 @@
+import { CommonModule } from '@angular/common';
+import { Component, OnDestroy, OnInit } from '@angular/core';
+import { FormsModule } from '@angular/forms';
+
+import { createApiClient } from '../../../../../src/api/client';
+import type { FinishGameResponse, ScoreboardResponse, SessionDetailResponse } from '../../../../../src/api/types';
+import { deriveGameplayPhase, isHostGameplayActionAllowed } from '../../../../../src/spa/gameplay-phase-machine';
+import { createVerticalSliceController } from '../../../../../src/spa/vertical-slice';
+import { clientHasNoAudioOutput, resolvePreferredLocale, subscribeToLocaleChanges, t } from '../../lobby-i18n';
+
+type SessionDetail = SessionDetailResponse;
+
+type LeaderboardEntry = FinishGameResponse['leaderboard'][number];
+type LeaderboardResponse = FinishGameResponse;
+
+@Component({
+  selector: 'app-host-shell',
+  standalone: true,
+  imports: [CommonModule, FormsModule],
+  template: `
+    <h2>{{ copy('host.title') }}</h2>
+
+    <div class="panel" [attr.data-client-has-no-audio-output]="clientHasNoAudioOutput">
+      <label>{{ copy('common.session_code') }} <input [(ngModel)]="sessionCode" /></label>
+      <label *ngIf="canStartRound">{{ copy('host.category') }} <input [(ngModel)]="categorySlug" /></label>
+      <button (click)="refreshSession()" [disabled]="loading">{{ copy('common.refresh') }}</button>
+      <button (click)="startRound()" [disabled]="loading || !canStartRound">{{ copy('host.start_round') }}</button>
+      <button (click)="showQuestion()" [disabled]="loading || !canShowQuestion">{{ copy('host.show_question') }}</button>
+      <button (click)="mixAnswers()" [disabled]="loading || !canMixAnswers">{{ copy('host.mix_answers') }}</button>
+      <button (click)="calculateScores()" [disabled]="loading || !canCalculateScores">{{ copy('host.calculate_scores') }}</button>
+      <button (click)="loadScoreboard()" [disabled]="loading || !canLoadScoreboard">{{ copy('host.load_scoreboard') }}</button>
+      <button (click)="startNextRound()" [disabled]="loading || !canStartNextRound">{{ copy('host.start_next_round') }}</button>
+      <button (click)="finishGame()" [disabled]="loading || !canFinishGame">{{ copy('host.finish_game') }}</button>
+      <button *ngIf="scoreboardError" (click)="loadScoreboard()" [disabled]="loading || !canLoadScoreboard">{{ copy('host.retry_scoreboard') }}</button>
+      <button *ngIf="nextRoundError" (click)="startNextRound()" [disabled]="loading || !canStartNextRound">{{ copy('host.retry_next_round') }}</button>
+      <button *ngIf="finishError" (click)="finishGame()" [disabled]="loading || !canFinishGame">{{ copy('host.retry_finish') }}</button>
+    </div>
+
+    <p *ngIf="session" class="hint">{{ copy('host.audio_locale_hint') }}: {{ locale }}</p>
+    <p *ngIf="error" class="error">{{ error }}</p>
+    <p *ngIf="nextRoundError" class="error">{{ nextRoundError }}</p>
+    <p *ngIf="finishError" class="error">{{ finishError }}</p>
+
+    <div *ngIf="session" class="panel">
+      <p><strong>{{ copy('common.status') }}:</strong> {{ session.session.status }} · {{ copy('common.round') }} {{ session.session.current_round }}</p>
+      <p><strong>{{ copy('common.round_question_id') }}:</strong> {{ roundQuestionId || '-' }}</p>
+      <p *ngIf="session.round_question"><strong>{{ copy('common.prompt') }}:</strong> {{ session.round_question.prompt }}</p>
+      <ul>
+        <li *ngFor="let p of session.players">{{ p.nickname }}: {{ p.score }}</li>
+      </ul>
+      <div class="panel" *ngIf="showRevealPanel">
+        <h3>Reveal</h3>
+        <p><strong>Korrekt svar:</strong> {{ session.reveal.correct_answer }}</p>
+        <p><strong>Spørgsmål:</strong> {{ session.reveal.prompt }}</p>
+        <div *ngIf="session.reveal.lies.length">
+          <strong>Løgne</strong>
+          <ul>
+            <li *ngFor="let lie of session.reveal.lies">{{ lie.nickname }} løj: {{ lie.text }}</li>
+          </ul>
+        </div>
+        <div *ngIf="session.reveal.guesses.length">
+          <strong>Gæt</strong>
+          <ul>
+            <li *ngFor="let guess of session.reveal.guesses">
+              {{ guess.nickname }} valgte {{ guess.selected_text }}
+              <span *ngIf="guess.is_correct">· korrekt</span>
+              <span *ngIf="!guess.is_correct && guess.fooled_player_nickname">· narret af {{ guess.fooled_player_nickname }}</span>
+              <span *ngIf="!guess.is_correct && !guess.fooled_player_nickname">· forkert</span>
+            </li>
+          </ul>
+        </div>
+      </div>
+      <div *ngIf="finalLeaderboard.length">
+        <h3>{{ copy('host.final_leaderboard') }}</h3>
+        <p *ngIf="finalWinner"><strong>{{ copy('host.winner') }}:</strong> {{ finalWinner.nickname }} ({{ finalWinner.score }} {{ copy('common.points_short') }})</p>
+        <ol>
+          <li *ngFor="let entry of finalLeaderboard">{{ entry.nickname }}: {{ entry.score }}</li>
+        </ol>
+      </div>
+      <pre *ngIf="finalLeaderboardPayload">{{ finalLeaderboardPayload }}</pre>
+    </div>
+  `,
+})
+export class HostShellComponent implements OnInit, OnDestroy {
+  locale = resolvePreferredLocale();
+  readonly clientHasNoAudioOutput = clientHasNoAudioOutput;
+
+  sessionCode = '';
+  categorySlug = 'general';
+  roundQuestionId = '';
+  loading = false;
+  error = '';
+  scoreboardError = '';
+  nextRoundError = '';
+  finishError = '';
+  scoreboardPayload = '';
+  finalLeaderboardPayload = '';
+  finalLeaderboard: LeaderboardEntry[] = [];
+  finalWinner: LeaderboardEntry | null = null;
+  session: SessionDetail | null = null;
+
+  private readonly api = createApiClient();
+  private readonly controller = createVerticalSliceController(this.api);
+  private unsubscribeLocale: (() => void) | null = null;
+
+  ngOnInit(): void {
+    this.unsubscribeLocale = subscribeToLocaleChanges((locale) => {
+      this.locale = locale;
+    });
+    if (typeof window === 'undefined') {
+      return;
+    }
+
+    const hashRoute = window.location.hash.replace(/^#\/?/, '');
+    const match = hashRoute.match(/^host(?:\/[^/]+)?(?:\/([^/?#]+))?/i);
+    const codeFromRoute = match?.[1] ?? '';
+    const storedCode = window.sessionStorage.getItem('wpp.host-session-code') ?? '';
+    const candidate = codeFromRoute || storedCode;
+
+    if (!candidate) {
+      return;
+    }
+
+    this.sessionCode = this.normalizeCode(candidate);
+    this.persistSessionCode(this.sessionCode);
+    void this.refreshSession();
+  }
+
+  ngOnDestroy(): void {
+    this.unsubscribeLocale?.();
+    this.unsubscribeLocale = null;
+  }
+
+  get gameplayPhase(): string | null {
+    return deriveGameplayPhase(this.session as any);
+  }
+
+  get canStartRound(): boolean {
+    return isHostGameplayActionAllowed(this.session as any, 'startRound');
+  }
+
+  get canShowQuestion(): boolean {
+    return isHostGameplayActionAllowed(this.session as any, 'showQuestion');
+  }
+
+  get canMixAnswers(): boolean {
+    return isHostGameplayActionAllowed(this.session as any, 'mixAnswers');
+  }
+
+  get canCalculateScores(): boolean {
+    return isHostGameplayActionAllowed(this.session as any, 'calculateScores');
+  }
+
+  get canLoadScoreboard(): boolean {
+    return isHostGameplayActionAllowed(this.session as any, 'loadScoreboard');
+  }
+
+  get canStartNextRound(): boolean {
+    return isHostGameplayActionAllowed(this.session as any, 'startNextRound');
+  }
+
+  get canFinishGame(): boolean {
+    return isHostGameplayActionAllowed(this.session as any, 'finishGame');
+  }
+
+  get showRevealPanel(): boolean {
+    return Boolean(this.session?.reveal && (this.gameplayPhase === 'reveal' || this.gameplayPhase === 'scoreboard'));
+  }
+
+  copy(key: string): string {
+    return t(key, this.locale);
+  }
+
+  private normalizeCode(value: string): string {
+    return value.trim().toUpperCase();
+  }
+
+  private persistSessionCode(code: string): void {
+    if (typeof window !== 'undefined') {
+      window.sessionStorage.setItem('wpp.host-session-code', code);
+    }
+  }
+
+  private async request<T>(path: string, method: 'GET' | 'POST', payload?: unknown): Promise<T> {
+    const response = await fetch(path, {
+      method,
+      headers: {
+        Accept: 'application/json',
+        ...(payload === undefined ? {} : { 'Content-Type': 'application/json' }),
+      },
+      ...(payload === undefined ? {} : { body: JSON.stringify(payload) }),
+      credentials: 'same-origin',
+    });
+
+    const body = await response.json().catch(() => ({}));
+    if (!response.ok) {
+      throw new Error((body as { error?: string }).error ?? `HTTP ${response.status}`);
+    }
+
+    return body as T;
+  }
+
+  async refreshSession(): Promise<void> {
+    this.loading = true;
+    this.error = '';
+    this.scoreboardError = '';
+    this.nextRoundError = '';
+    this.finishError = '';
+    try {
+      const state = await this.controller.hydrateLobby(this.sessionCode);
+      if (!state.session || state.errorMessage) {
+        throw new Error(state.errorMessage ?? this.copy('common.unknown_error'));
+      }
+      this.session = state.session as SessionDetail;
+      this.sessionCode = this.session.session.code;
+      this.persistSessionCode(this.sessionCode);
+      this.roundQuestionId = this.session.round_question?.id ? String(this.session.round_question.id) : '';
+      if (this.session.session.status !== 'finished') {
+        this.resetFinalLeaderboard();
+      }
+      this.syncRouteFromSession();
+    } catch (error) {
+      this.error = `${this.copy('host.session_refresh_failed')}: ${(error as Error).message}`;
+    } finally {
+      this.loading = false;
+    }
+  }
+
+  async startRound(): Promise<void> {
+    if (!this.canStartRound) {
+      return;
+    }
+
+    await this.runAction(async () => {
+      const state = await this.controller.startRound(this.sessionCode, this.categorySlug.trim());
+      if (!state.session || state.errorMessage) {
+        throw new Error(state.errorMessage ?? this.copy('common.unknown_error'));
+      }
+      this.session = state.session as SessionDetail;
+      this.sessionCode = this.session.session.code;
+      this.persistSessionCode(this.sessionCode);
+      this.roundQuestionId = this.session.round_question?.id ? String(this.session.round_question.id) : '';
+      this.resetFinalLeaderboard();
+      this.syncRouteFromSession();
+    });
+  }
+
+  async showQuestion(): Promise<void> {
+    if (!this.canShowQuestion) {
+      return;
+    }
+
+    await this.runAction(async () => {
+      const code = this.normalizeCode(this.sessionCode);
+      await this.request(`/lobby/sessions/${encodeURIComponent(code)}/questions/show`, 'POST', {});
+      await this.refreshSession();
+    });
+  }
+
+  async mixAnswers(): Promise<void> {
+    if (!this.canMixAnswers) {
+      return;
+    }
+
+    await this.runAction(async () => {
+      const code = this.normalizeCode(this.sessionCode);
+      const roundQuestionId = this.roundQuestionId.trim();
+      await this.request(`/lobby/sessions/${encodeURIComponent(code)}/questions/${roundQuestionId}/answers/mix`, 'POST', {});
+      await this.refreshSession();
+    });
+  }
+
+  async calculateScores(): Promise<void> {
+    if (!this.canCalculateScores) {
+      return;
+    }
+
+    await this.runAction(async () => {
+      const code = this.normalizeCode(this.sessionCode);
+      const roundQuestionId = this.roundQuestionId.trim();
+      await this.request(`/lobby/sessions/${encodeURIComponent(code)}/questions/${roundQuestionId}/scores/calculate`, 'POST', {});
+      await this.refreshSession();
+    });
+  }
+
+  async loadScoreboard(): Promise<void> {
+    if (!this.canLoadScoreboard) {
+      return;
+    }
+
+    this.loading = true;
+    this.scoreboardError = '';
+    this.error = '';
+    try {
+      const code = this.normalizeCode(this.sessionCode);
+      const payload = await this.request<ScoreboardResponse>(`/lobby/sessions/${encodeURIComponent(code)}/scoreboard`, 'GET');
+      this.scoreboardPayload = JSON.stringify(payload, null, 2);
+      await this.refreshSession();
+    } catch (error) {
+      this.scoreboardError = `${this.copy('host.scoreboard_failed')}: ${(error as Error).message}`;
+    } finally {
+      this.loading = false;
+    }
+  }
+
+  async startNextRound(): Promise<void> {
+    if (!this.canStartNextRound) {
+      return;
+    }
+
+    this.loading = true;
+    this.nextRoundError = '';
+    this.error = '';
+    try {
+      const code = this.normalizeCode(this.sessionCode);
+      if (!code) {
+        throw new Error(this.copy('host.session_code_required'));
+      }
+      await this.request(`/lobby/sessions/${encodeURIComponent(code)}/rounds/next`, 'POST', {});
+      this.resetFinalLeaderboard();
+      await this.refreshSession();
+    } catch (error) {
+      this.nextRoundError = `${this.copy('host.next_round_failed')}: ${(error as Error).message}`;
+    } finally {
+      this.loading = false;
+    }
+  }
+
+  async finishGame(): Promise<void> {
+    if (!this.canFinishGame) {
+      return;
+    }
+
+    this.loading = true;
+    this.finishError = '';
+    this.error = '';
+    try {
+      const code = this.normalizeCode(this.sessionCode);
+      if (!code) {
+        throw new Error(this.copy('host.session_code_required'));
+      }
+      const payload = await this.request<LeaderboardResponse>(`/lobby/sessions/${encodeURIComponent(code)}/finish`, 'POST', {});
+      this.finalLeaderboardPayload = JSON.stringify(payload, null, 2);
+      this.finalLeaderboard = [...payload.leaderboard].sort((a, b) => {
+        if (b.score !== a.score) {
+          return b.score - a.score;
+        }
+        return a.nickname.localeCompare(b.nickname);
+      });
+      this.finalWinner = payload.winner ?? this.finalLeaderboard[0] ?? null;
+      await this.refreshSession();
+    } catch (error) {
+      this.finishError = `${this.copy('host.finish_game_failed')}: ${(error as Error).message}`;
+    } finally {
+      this.loading = false;
+    }
+  }
+
+  private resetFinalLeaderboard(): void {
+    this.scoreboardPayload = '';
+    this.finalLeaderboardPayload = '';
+    this.finalLeaderboard = [];
+    this.finalWinner = null;
+  }
+
+  private syncRouteFromSession(): void {
+    if (!this.session) {
+      return;
+    }
+
+    const phase = this.gameplayPhase ?? this.session.session.status ?? 'lobby';
+    const code = this.normalizeCode(this.session.session.code || this.sessionCode);
+    if (!code) {
+      return;
+    }
+
+    const targetPath = `#/host/${encodeURIComponent(phase)}/${encodeURIComponent(code)}`;
+    if (typeof window === 'undefined' || window.location.hash === targetPath) {
+      return;
+    }
+
+    window.history.replaceState(window.history.state, '', targetPath);
+  }
+
+  private async runAction(action: () => Promise<void>): Promise<void> {
+    this.loading = true;
+    this.error = '';
+    try {
+      await action();
+    } catch (error) {
+      this.error = (error as Error).message;
+    } finally {
+      this.loading = false;
+    }
+  }
+}

frontend/angular/src/app/features/player/player-shell.component.spec.ts

@@ -0,0 +1,695 @@
+import { afterEach, describe, expect, it, vi } from 'vitest';
+
+import lobbyCatalog from '../../../../../../shared/i18n/lobby.json';
+import { PlayerShellComponent } from './player-shell.component';
+
+type FetchMock = ReturnType<typeof vi.fn>;
+
+function jsonResponse(status: number, body: unknown) {
+  return {
+    ok: status >= 200 && status < 300,
+    status,
+    json: vi.fn().mockResolvedValue(body),
+  } as unknown as Response;
+}
+
+function sessionDetailPayload(
+  status: string,
+  options?: {
+    currentPhase?: string;
+    answers?: string[];
+    players?: Array<{ id: number; nickname: string; score: number }>;
+    roundQuestionId?: number | null;
+    reveal?: {
+      correct_answer: string;
+      prompt?: string;
+      lies?: Array<{ player_id: number; nickname: string; text: string; created_at?: string }>;
+      guesses?: Array<{
+        player_id: number;
+        nickname: string;
+        selected_text: string;
+        is_correct: boolean;
+        fooled_player_id: number | null;
+        fooled_player_nickname?: string;
+        created_at?: string;
+      }>;
+    } | null;
+  }
+) {
+  const answers = options?.answers ?? [];
+  const roundQuestionId = options?.roundQuestionId ?? 11;
+
+  return {
+    session: {
+      code: 'ABCD12',
+      status,
+      host_id: null,
+      current_round: 1,
+      players_count: (options?.players ?? []).length,
+    },
+    round_question:
+      roundQuestionId === null
+        ? null
+        : {
+            id: roundQuestionId,
+            round_number: 1,
+            prompt: 'Q?',
+            shown_at: '2026-01-01T00:00:00Z',
+            answers: answers.map((text) => ({ text })),
+          },
+    players: (options?.players ?? []).map((player) => ({
+      ...player,
+      is_connected: true,
+    })),
+    reveal:
+      options?.reveal === undefined || options?.reveal === null
+        ? null
+        : {
+            round_question_id: roundQuestionId,
+            round_number: 1,
+            prompt: options.reveal.prompt ?? 'Q?',
+            correct_answer: options.reveal.correct_answer,
+            lies: (options.reveal.lies ?? []).map((lie) => ({
+              ...lie,
+              created_at: lie.created_at ?? '2026-01-01T00:00:05Z',
+            })),
+            guesses: (options.reveal.guesses ?? []).map((guess) => ({
+              ...guess,
+              created_at: guess.created_at ?? '2026-01-01T00:00:10Z',
+            })),
+          },
+    phase_view_model: {
+      status,
+      current_phase: options?.currentPhase ?? status,
+      round_number: 1,
+      players_count: (options?.players ?? []).length,
+      constraints: {
+        min_players_to_start: 2,
+        max_players_mvp: 8,
+        min_players_reached: true,
+        max_players_allowed: true,
+      },
+      readiness: {
+        question_ready: (options?.currentPhase ?? status) !== 'lobby',
+        scoreboard_ready: (options?.currentPhase ?? status) === 'reveal' || (options?.currentPhase ?? status) === 'scoreboard',
+      },
+      host: {
+        can_start_round: false,
+        can_show_question: false,
+        can_mix_answers: false,
+        can_calculate_scores: false,
+        can_reveal_scoreboard: false,
+        can_start_next_round: false,
+        can_finish_game: false,
+      },
+      player: {
+        can_join: (options?.currentPhase ?? status) === 'lobby',
+        can_submit_lie: (options?.currentPhase ?? status) === 'lie',
+        can_submit_guess: (options?.currentPhase ?? status) === 'guess',
+        can_view_final_result: (options?.currentPhase ?? status) === 'finished',
+      },
+    },
+  };
+}
+
+describe('PlayerShellComponent gameplay wiring', () => {
+  afterEach(() => {
+    vi.useRealTimers();
+    vi.restoreAllMocks();
+  });
+
+  it('clears selected guess when refreshed status is no longer guess', async () => {
+    const fetchMock: FetchMock = vi.fn().mockResolvedValue(
+      jsonResponse(200, sessionDetailPayload('reveal', { answers: ['A'] }))
+    );
+
+    vi.stubGlobal('fetch', fetchMock);
+
+    const component = new PlayerShellComponent();
+    component.sessionCode = 'abcd12';
+    component.selectedGuess = 'A';
+
+    await component.refreshSession();
+
+    expect(fetchMock).toHaveBeenCalledWith(
+      '/lobby/sessions/ABCD12',
+      expect.objectContaining({ method: 'GET' })
+    );
+    expect(component.selectedGuess).toBe('');
+  });
+
+  it('surfaces lie submit error and allows retry success flow', async () => {
+    const fetchMock: FetchMock = vi
+      .fn()
+      .mockResolvedValueOnce(jsonResponse(500, { error: 'Temporary submit outage' }))
+      .mockResolvedValueOnce(jsonResponse(201, { lie: { id: 1, player_id: 9, round_question_id: 11, text: 'my lie', created_at: '2026-01-01T00:00:01Z' }, window: { lie_deadline_at: '2026-01-01T00:00:45Z' } }))
+      .mockResolvedValueOnce(jsonResponse(200, sessionDetailPayload('guess', { answers: ['A', 'B'] })));
+
+    vi.stubGlobal('fetch', fetchMock);
+
+    const component = new PlayerShellComponent();
+    component.sessionCode = 'ABCD12';
+    component.playerId = 9;
+    component.sessionToken = 'token-1';
+    component.lieText = 'my lie';
+    component.session = {
+      ...(sessionDetailPayload('lie', { roundQuestionId: 11 }) as any),
+      round_question: { id: 11, prompt: 'Q?', answers: [] },
+    };
+
+    await component.submitLie();
+
+    expect(fetchMock).toHaveBeenNthCalledWith(
+      1,
+      '/lobby/sessions/ABCD12/questions/11/lies/submit',
+      expect.objectContaining({
+        method: 'POST',
+        body: JSON.stringify({ player_id: 9, session_token: 'token-1', text: 'my lie' }),
+      })
+    );
+    expect(component.submitError?.kind).toBe('lie');
+    expect(component.submitError?.message).toContain('Lie submit failed: Temporary submit outage');
+
+    await component.submitLie();
+
+    expect(component.submitError).toBeNull();
+    expect(component.session?.session.status).toBe('guess');
+    expect(fetchMock).toHaveBeenCalledTimes(3);
+  });
+
+  it('builds final leaderboard in finished status without legacy page hop', async () => {
+    const fetchMock: FetchMock = vi.fn().mockResolvedValue(
+      jsonResponse(
+        200,
+        sessionDetailPayload('finished', {
+          roundQuestionId: null,
+          players: [
+            { id: 2, nickname: 'Mads', score: 150 },
+            { id: 1, nickname: 'Luna', score: 320 },
+          ],
+        })
+      )
+    );
+
+    vi.stubGlobal('fetch', fetchMock);
+
+    const component = new PlayerShellComponent();
+    component.sessionCode = 'ABCD12';
+
+    await component.refreshSession();
+
+    expect(component.finalLeaderboard.map((entry) => entry.nickname)).toEqual(['Luna', 'Mads']);
+  });
+
+  it('hydrates canonical reveal payload after guess -> reveal', async () => {
+    const fetchMock: FetchMock = vi.fn().mockResolvedValue(
+      jsonResponse(
+        200,
+        sessionDetailPayload('reveal', {
+          answers: ['A', 'B'],
+          reveal: {
+            correct_answer: 'A',
+            lies: [{ player_id: 3, nickname: 'Løgnhals', text: 'B' }],
+            guesses: [
+              {
+                player_id: 9,
+                nickname: 'Detektiv',
+                selected_text: 'B',
+                is_correct: false,
+                fooled_player_id: 3,
+                fooled_player_nickname: 'Løgnhals',
+              },
+              {
+                player_id: 10,
+                nickname: 'Sandhed',
+                selected_text: 'A',
+                is_correct: true,
+                fooled_player_id: null,
+              },
+            ],
+          },
+        })
+      )
+    );
+
+    vi.stubGlobal('fetch', fetchMock);
+
+    const component = new PlayerShellComponent();
+    component.sessionCode = 'ABCD12';
+
+    await component.refreshSession();
+
+    expect(component.session?.reveal?.correct_answer).toBe('A');
+    expect(component.session?.reveal?.lies[0]).toMatchObject({ player_id: 3, nickname: 'Løgnhals', text: 'B' });
+    expect(component.session?.reveal?.guesses[0]).toMatchObject({
+      player_id: 9,
+      nickname: 'Detektiv',
+      selected_text: 'B',
+      is_correct: false,
+      fooled_player_id: 3,
+      fooled_player_nickname: 'Løgnhals',
+    });
+    expect(component.session?.reveal?.guesses[1]).toMatchObject({
+      player_id: 10,
+      nickname: 'Sandhed',
+      selected_text: 'A',
+      is_correct: true,
+      fooled_player_id: null,
+    });
+  });
+
+  it('surfaces guess submit error and retries with selected answer payload', async () => {
+    const fetchMock: FetchMock = vi
+      .fn()
+      .mockResolvedValueOnce(jsonResponse(503, { error: 'Guess queue busy' }))
+      .mockResolvedValueOnce(jsonResponse(201, { guess: { id: 2, player_id: 9, round_question_id: 11, selected_text: 'B', is_correct: false, fooled_player_id: 3, created_at: '2026-01-01T00:00:10Z' }, window: { guess_deadline_at: '2026-01-01T00:01:30Z' } }))
+      .mockResolvedValueOnce(jsonResponse(200, sessionDetailPayload('reveal', { answers: ['A', 'B'] })));
+
+    vi.stubGlobal('fetch', fetchMock);
+
+    const component = new PlayerShellComponent();
+    component.sessionCode = ' abcd12 ';
+    component.playerId = 9;
+    component.sessionToken = 'token-1';
+    component.selectedGuess = 'B';
+    component.session = {
+      ...(sessionDetailPayload('guess', { answers: ['A', 'B'], roundQuestionId: 11 }) as any),
+      round_question: { id: 11, prompt: 'Q?', answers: [{ text: 'A' }, { text: 'B' }] },
+    };
+
+    await component.submitGuess();
+
+    expect(fetchMock).toHaveBeenNthCalledWith(
+      1,
+      '/lobby/sessions/ABCD12/questions/11/guesses/submit',
+      expect.objectContaining({
+        method: 'POST',
+        body: JSON.stringify({ player_id: 9, session_token: 'token-1', selected_text: 'B' }),
+      })
+    );
+    expect(component.submitError?.kind).toBe('guess');
+    expect(component.submitError?.message).toContain('Guess submit failed: Guess queue busy');
+
+    await component.submitGuess();
+
+    expect(component.submitError).toBeNull();
+    expect(component.session?.session.status).toBe('reveal');
+    expect(component.selectedGuess).toBe('');
+    expect(fetchMock).toHaveBeenCalledTimes(3);
+  });
+
+  it('blocks illegal player guess submission outside canonical guess phase', async () => {
+    const fetchMock: FetchMock = vi.fn();
+    vi.stubGlobal('fetch', fetchMock);
+
+    const component = new PlayerShellComponent();
+    component.sessionCode = 'ABCD12';
+    component.playerId = 9;
+    component.sessionToken = 'token-1';
+    component.selectedGuess = 'B';
+
+    for (const status of ['lie', 'reveal', 'scoreboard'] as const) {
+      component.session = {
+        ...(sessionDetailPayload(status, { answers: ['A', 'B'] }) as any),
+        round_question: { id: 11, prompt: 'Q?', answers: [{ text: 'A' }, { text: 'B' }] },
+      };
+
+      await component.submitGuess();
+    }
+
+    expect(component.canSubmitGuess).toBe(false);
+    expect(fetchMock).not.toHaveBeenCalled();
+  });
+
+  it('auto-refreshes player session to avoid host/player state desync between rounds', async () => {
+    vi.useFakeTimers();
+
+    const fetchMock: FetchMock = vi
+      .fn()
+      .mockResolvedValueOnce(jsonResponse(200, sessionDetailPayload('scoreboard', { roundQuestionId: null })))
+      .mockResolvedValueOnce(jsonResponse(200, sessionDetailPayload('lobby', { roundQuestionId: null })));
+
+    vi.stubGlobal('fetch', fetchMock);
+
+    const component = new PlayerShellComponent();
+    component.sessionCode = 'ABCD12';
+
+    await component.refreshSession();
+    expect(component.session?.session.status).toBe('scoreboard');
+
+    await vi.advanceTimersByTimeAsync(3100);
+
+    expect(fetchMock).toHaveBeenCalledTimes(2);
+    expect(component.session?.session.status).toBe('lobby');
+
+    component.ngOnDestroy();
+  });
+
+  it('enters reconnecting state when network request fails while online', async () => {
+    vi.stubGlobal('navigator', { onLine: true });
+
+    const fetchMock: FetchMock = vi.fn().mockRejectedValueOnce(new TypeError('Failed to fetch'));
+    vi.stubGlobal('fetch', fetchMock);
+
+    const component = new PlayerShellComponent();
+    component.sessionCode = 'ABCD12';
+
+    await component.refreshSession();
+
+    expect(component.connectionState === 'reconnecting' || component.connectionState === 'online').toBe(true);
+    expect(component.error).toContain('Session refresh failed:');
+  });
+
+  it('uses offline state when browser reports disconnected network', async () => {
+    vi.stubGlobal('navigator', { onLine: false });
+
+    const fetchMock: FetchMock = vi.fn().mockRejectedValue(new TypeError('Failed to fetch'));
+    vi.stubGlobal('fetch', fetchMock);
+
+    const component = new PlayerShellComponent();
+    component.sessionCode = 'ABCD12';
+
+    await component.refreshSession();
+
+    expect(component.connectionState).toBe('offline');
+    expect(component.error).toContain('Session refresh failed');
+  });
+
+  it('tracks loading transition message for join action', async () => {
+    let resolveJoin: ((value: Response) => void) | null = null;
+    const fetchMock: FetchMock = vi.fn().mockImplementation(
+      () =>
+        new Promise<Response>((resolve) => {
+          resolveJoin = resolve;
+        })
+    );
+    vi.stubGlobal('fetch', fetchMock);
+
+    const component = new PlayerShellComponent();
+    component.sessionCode = 'ABCD12';
+    component.nickname = 'Luna';
+
+    const joinPromise = component.joinSession();
+
+    expect(component.loading).toBe(true);
+    expect(component.loadingMessage).toBe('Joining session… restoring your player state.');
+
+    resolveJoin?.(jsonResponse(201, sessionDetailPayload('lobby', { roundQuestionId: null })));
+    await joinPromise;
+
+    expect(component.loading).toBe(false);
+    expect(component.loadingTransition).toBeNull();
+  });
+
+  it('returnToJoin clears persisted session context and transient state', () => {
+    const values = new Map<string, string>();
+    const localStorage = {
+      getItem: vi.fn((key: string) => values.get(key) ?? null),
+      setItem: vi.fn((key: string, value: string) => {
+        values.set(key, value);
+      }),
+      removeItem: vi.fn((key: string) => {
+        values.delete(key);
+      }),
+    };
+
+    vi.stubGlobal('window', {
+      addEventListener: vi.fn(),
+      removeEventListener: vi.fn(),
+      localStorage,
+    });
+
+    values.set('wpp.session-context', JSON.stringify({ sessionCode: 'ABCD12', playerId: 9, token: 'tok-1' }));
+
+    const component = new PlayerShellComponent();
+    component.sessionCode = 'ABCD12';
+    component.playerId = 9;
+    component.sessionToken = 'tok-1';
+    component.error = 'Session refresh failed';
+    component.submitError = { kind: 'guess', message: 'Guess submit failed' };
+    component.session = {
+      session: { code: 'ABCD12', status: 'guess', current_round: 1 },
+      round_question: { id: 11, prompt: 'Q?', answers: [{ text: 'A' }] },
+      players: [],
+    };
+
+    component.returnToJoin();
+
+    expect(component.playerId).toBe(0);
+    expect(component.sessionToken).toBe('');
+    expect(component.session).toBeNull();
+    expect(component.error).toBe('');
+    expect(component.submitError).toBeNull();
+    expect(values.get('wpp.session-context')).toBeUndefined();
+  });
+
+  it('prefers canonical current_phase for player reveal panel and routing when status lags behind', async () => {
+    const fetchMock: FetchMock = vi.fn().mockResolvedValue(
+      jsonResponse(200, sessionDetailPayload('reveal', { currentPhase: 'scoreboard', roundQuestionId: 11, reveal: { correct_answer: 'A' } }))
+    );
+
+    vi.stubGlobal('fetch', fetchMock);
+
+    const replaceState = vi.fn();
+    const localStorage = { getItem: vi.fn().mockReturnValue(null), setItem: vi.fn(), removeItem: vi.fn() };
+    vi.stubGlobal('window', {
+      location: { hash: '#/player/reveal/ABCD12' },
+      history: { state: null, replaceState },
+      localStorage,
+      addEventListener: vi.fn(),
+      removeEventListener: vi.fn(),
+    });
+
+    const component = new PlayerShellComponent();
+    component.sessionCode = 'ABCD12';
+
+    await component.refreshSession();
+
+    expect(component.gameplayPhase).toBe('scoreboard');
+    expect(component.showRevealPanel).toBe(true);
+    expect(component.showGuessControls).toBe(false);
+    expect(replaceState).toHaveBeenCalledWith(null, '', '#/player/scoreboard/ABCD12');
+  });
+
+  it('syncs player hash-route with latest phase during periodic state sync', async () => {
+    vi.useFakeTimers();
+
+    const fetchMock: FetchMock = vi
+      .fn()
+      .mockResolvedValueOnce(jsonResponse(200, sessionDetailPayload('scoreboard', { roundQuestionId: null })))
+      .mockResolvedValueOnce(jsonResponse(200, sessionDetailPayload('lobby', { roundQuestionId: null })));
+
+    vi.stubGlobal('fetch', fetchMock);
+
+    const replaceState = vi.fn();
+    const localStorage = { getItem: vi.fn().mockReturnValue(null), setItem: vi.fn(), removeItem: vi.fn() };
+    vi.stubGlobal('window', {
+      location: { hash: '#/player/scoreboard/ABCD12' },
+      history: { state: null, replaceState },
+      localStorage,
+      addEventListener: vi.fn(),
+      removeEventListener: vi.fn(),
+    });
+
+    const component = new PlayerShellComponent();
+    component.sessionCode = 'ABCD12';
+
+    await component.refreshSession();
+    await vi.advanceTimersByTimeAsync(3100);
+
+    expect(replaceState).toHaveBeenCalledWith(null, '', '#/player/lobby/ABCD12');
+
+    component.ngOnDestroy();
+  });
+
+  it('silences active media elements when secondary-device audio guard is installed', () => {
+    const pauseAudio = vi.fn();
+    const pauseVideo = vi.fn();
+    const audioElement = { muted: false, pause: pauseAudio };
+    const videoElement = { muted: false, pause: pauseVideo };
+    const querySelectorAll = vi.fn().mockReturnValue([audioElement, videoElement]);
+
+    vi.stubGlobal('document', { querySelectorAll });
+    vi.stubGlobal('window', {
+      location: { hash: '', search: '' },
+      history: { state: null, replaceState: vi.fn() },
+      localStorage: { getItem: vi.fn().mockReturnValue('en'), setItem: vi.fn(), removeItem: vi.fn() },
+      sessionStorage: { getItem: vi.fn().mockReturnValue(null), setItem: vi.fn(), removeItem: vi.fn() },
+      HTMLMediaElement: { prototype: { play: vi.fn().mockResolvedValue(undefined) } },
+      addEventListener: vi.fn(),
+      removeEventListener: vi.fn(),
+    });
+    vi.stubGlobal('navigator', { language: 'en-US', onLine: true });
+
+    const component = new PlayerShellComponent();
+    component.ngOnInit();
+
+    expect(querySelectorAll).toHaveBeenCalledWith('audio,video');
+    expect(audioElement.muted).toBe(true);
+    expect(videoElement.muted).toBe(true);
+    expect(pauseAudio).toHaveBeenCalledTimes(1);
+    expect(pauseVideo).toHaveBeenCalledTimes(1);
+
+    component.ngOnDestroy();
+  });
+
+  it('installs secondary-device audio guard while player shell is mounted', async () => {
+    const originalPlay = vi.fn().mockRejectedValue(new Error('original play'));
+    const mediaPrototype = { play: originalPlay };
+
+    vi.stubGlobal('window', {
+      location: { hash: '', search: '' },
+      history: { state: null, replaceState: vi.fn() },
+      localStorage: { getItem: vi.fn().mockReturnValue('en'), setItem: vi.fn(), removeItem: vi.fn() },
+      sessionStorage: { getItem: vi.fn().mockReturnValue(null), setItem: vi.fn(), removeItem: vi.fn() },
+      HTMLMediaElement: { prototype: mediaPrototype },
+      addEventListener: vi.fn(),
+      removeEventListener: vi.fn(),
+    });
+    vi.stubGlobal('navigator', { language: 'en-US', onLine: true });
+
+    const component = new PlayerShellComponent();
+    component.ngOnInit();
+
+    const pause = vi.fn();
+    const audioElement = { muted: false, defaultMuted: false, volume: 1, pause };
+
+    await expect(mediaPrototype.play.call(audioElement)).resolves.toBeUndefined();
+    expect(audioElement.muted).toBe(true);
+    expect(audioElement.defaultMuted).toBe(true);
+    expect(audioElement.volume).toBe(0);
+    expect(pause).toHaveBeenCalledTimes(1);
+
+    component.ngOnDestroy();
+
+    await expect(mediaPrototype.play()).rejects.toThrow('original play');
+  });
+
+  it('keeps audio guard active until the last mounted player shell is destroyed', async () => {
+    const originalPlay = vi.fn().mockRejectedValue(new Error('original play'));
+    const mediaPrototype = { play: originalPlay };
+
+    vi.stubGlobal('window', {
+      location: { hash: '', search: '' },
+      history: { state: null, replaceState: vi.fn() },
+      localStorage: { getItem: vi.fn().mockReturnValue('en'), setItem: vi.fn(), removeItem: vi.fn() },
+      sessionStorage: { getItem: vi.fn().mockReturnValue(null), setItem: vi.fn(), removeItem: vi.fn() },
+      HTMLMediaElement: { prototype: mediaPrototype },
+      addEventListener: vi.fn(),
+      removeEventListener: vi.fn(),
+    });
+    vi.stubGlobal('navigator', { language: 'en-US', onLine: true });
+
+    const firstComponent = new PlayerShellComponent();
+    const secondComponent = new PlayerShellComponent();
+
+    firstComponent.ngOnInit();
+    secondComponent.ngOnInit();
+
+    await expect(mediaPrototype.play()).resolves.toBeUndefined();
+
+    firstComponent.ngOnDestroy();
+    await expect(mediaPrototype.play()).resolves.toBeUndefined();
+
+    secondComponent.ngOnDestroy();
+    await expect(mediaPrototype.play()).rejects.toThrow('original play');
+  });
+
+  it('does not trigger original media play during player-shell init path', () => {
+    const originalPlay = vi.fn().mockResolvedValue(undefined);
+    const mediaPrototype = { play: originalPlay };
+
+    vi.stubGlobal('window', {
+      location: { hash: '', search: '' },
+      history: { state: null, replaceState: vi.fn() },
+      localStorage: { getItem: vi.fn().mockReturnValue('en'), setItem: vi.fn(), removeItem: vi.fn() },
+      sessionStorage: { getItem: vi.fn().mockReturnValue(null), setItem: vi.fn(), removeItem: vi.fn() },
+      HTMLMediaElement: { prototype: mediaPrototype },
+      addEventListener: vi.fn(),
+      removeEventListener: vi.fn(),
+    });
+    vi.stubGlobal('navigator', { language: 'en-US', onLine: true });
+
+    const component = new PlayerShellComponent();
+    component.ngOnInit();
+
+    expect(originalPlay).not.toHaveBeenCalled();
+
+    component.ngOnDestroy();
+  });
+
+  it('keeps primary-device playback untouched when no-audio capability is disabled', async () => {
+    const originalPlay = vi.fn().mockResolvedValue(undefined);
+    const mediaPrototype = { play: originalPlay };
+
+    vi.stubGlobal('window', {
+      location: { hash: '', search: '' },
+      history: { state: null, replaceState: vi.fn() },
+      localStorage: { getItem: vi.fn().mockReturnValue('en'), setItem: vi.fn(), removeItem: vi.fn() },
+      sessionStorage: { getItem: vi.fn().mockReturnValue(null), setItem: vi.fn(), removeItem: vi.fn() },
+      HTMLMediaElement: { prototype: mediaPrototype },
+      addEventListener: vi.fn(),
+      removeEventListener: vi.fn(),
+    });
+    vi.stubGlobal('navigator', { language: 'en-US', onLine: true });
+
+    const component = new PlayerShellComponent();
+    (component as any).clientHasNoAudioOutput = false;
+
+    component.ngOnInit();
+
+    await expect(mediaPrototype.play()).resolves.toBeUndefined();
+    expect(mediaPrototype.play).toBe(originalPlay);
+    expect((mediaPrototype as any).__wppSecondaryDeviceAudioGuard__).toBeUndefined();
+
+    component.ngOnDestroy();
+  });
+
+  it('resolves i18n warning copy from shared catalog without key fallback', () => {
+    const component = new PlayerShellComponent();
+
+    const notice = component.copy('player.audio_policy_notice');
+    const expected = lobbyCatalog.frontend.ui.player.audio_policy_notice[component.locale];
+
+    expect(notice).toBe(expected);
+    expect(notice).not.toBe('player.audio_policy_notice');
+  });
+
+  it('gates template warning notice on the no-audio-output capability flag', () => {
+    const templateSource = String((PlayerShellComponent as any).ɵcmp?.template);
+
+    expect(templateSource).toContain('clientHasNoAudioOutput');
+
+    const component = new PlayerShellComponent();
+    expect(component.copy('player.audio_policy_notice')).not.toBe('player.audio_policy_notice');
+    expect(component.clientHasNoAudioOutput).toBe(true);
+
+    (component as any).clientHasNoAudioOutput = false;
+    expect(component.clientHasNoAudioOutput).toBe(false);
+  });
+
+  it('keeps phone client controls phase-specific and low-complexity', () => {
+    const component = new PlayerShellComponent();
+
+    expect(component.showJoinControls).toBe(true);
+    expect(component.showLieControls).toBe(false);
+    expect(component.showGuessControls).toBe(false);
+    expect(component.showFinalLeaderboard).toBe(false);
+
+    component.session = sessionDetailPayload('lie') as any;
+    component.playerId = 9;
+    component.sessionToken = 'tok';
+    expect(component.showJoinControls).toBe(false);
+    expect(component.showLieControls).toBe(true);
+    expect(component.showGuessControls).toBe(false);
+
+    component.session = sessionDetailPayload('guess', { answers: ['A', 'B'] }) as any;
+    expect(component.showLieControls).toBe(false);
+    expect(component.showGuessControls).toBe(true);
+
+    component.session = sessionDetailPayload('finished', { players: [{ id: 1, nickname: 'Luna', score: 8 }] }) as any;
+    expect(component.showGuessControls).toBe(false);
+    expect(component.showFinalLeaderboard).toBe(true);
+  });
+
+});

frontend/angular/src/app/features/player/player-shell.component.ts

@@ -0,0 +1,620 @@
+import { CommonModule } from '@angular/common';
+import { Component, OnDestroy, OnInit } from '@angular/core';
+import { FormsModule } from '@angular/forms';
+
+import { createApiClient } from '../../../../../src/api/client';
+import type { SessionDetailResponse } from '../../../../../src/api/types';
+import {
+  deriveGameplayPhase,
+  isPlayerGameplayActionAllowed,
+} from '../../../../../src/spa/gameplay-phase-machine';
+import { createSessionContextStore } from '../../../../../src/spa/session-context-store';
+import { createVerticalSliceController } from '../../../../../src/spa/vertical-slice';
+import { clientHasNoAudioOutput, resolvePreferredLocale, subscribeToLocaleChanges, t } from '../../lobby-i18n';
+
+type SessionDetail = SessionDetailResponse;
+
+type ConnectionState = 'online' | 'reconnecting' | 'offline';
+type LoadingTransition = 'refresh' | 'join' | 'submit-lie' | 'submit-guess' | null;
+
+type GuardableMediaElement = {
+  muted?: boolean;
+  defaultMuted?: boolean;
+  volume?: number;
+  pause?: () => void;
+};
+
+type MediaPrototypeWithGuardState = {
+  play?: (this: GuardableMediaElement) => Promise<void>;
+  __wppSecondaryDeviceAudioGuard__?: {
+    originalPlay: (this: GuardableMediaElement) => Promise<void>;
+    installs: number;
+  };
+};
+
+
+function resolveLocalStorage(): Storage | undefined {
+  if (typeof window === 'undefined') {
+    return undefined;
+  }
+  return window.localStorage;
+}
+
+@Component({
+  selector: 'app-player-shell',
+  standalone: true,
+  imports: [CommonModule, FormsModule],
+  template: `
+    <h2>{{ copy('player.title') }}</h2>
+    <p *ngIf="clientHasNoAudioOutput" class="hint">{{ copy('player.audio_policy_notice') }}</p>
+
+    <div class="panel" [attr.data-client-has-no-audio-output]="clientHasNoAudioOutput">
+      <label>{{ copy('common.session_code') }} <input [(ngModel)]="sessionCode" /></label>
+      <label *ngIf="showJoinControls">{{ copy('player.nickname') }} <input [(ngModel)]="nickname" /></label>
+      <button (click)="refreshSession()" [disabled]="loading">{{ copy('common.refresh') }}</button>
+      <button *ngIf="showJoinControls" (click)="joinSession()" [disabled]="loading">{{ copy('player.join') }}</button>
+    </div>
+
+    <p *ngIf="connectionState === 'reconnecting'" class="error">
+      {{ copy('player.reconnecting_text') }}
+      <button type="button" (click)="retryReconnect()" [disabled]="loading">{{ copy('player.retry_now') }}</button>
+      <button type="button" (click)="returnToJoin()" [disabled]="loading">{{ copy('common.back_to_join') }}</button>
+    </p>
+    <p *ngIf="connectionState === 'offline'" class="error">
+      {{ copy('player.offline_text') }}
+      <button type="button" (click)="retryReconnect()" [disabled]="loading">{{ copy('player.retry_now') }}</button>
+      <button type="button" (click)="returnToJoin()" [disabled]="loading">{{ copy('common.back_to_join') }}</button>
+    </p>
+
+    <p *ngIf="loading" class="hint">{{ loadingMessage }}</p>
+
+    <div class="panel" *ngIf="session">
+      <p><strong>{{ copy('common.status') }}:</strong> {{ session.session.status }}</p>
+      <p *ngIf="session.round_question"><strong>{{ copy('common.prompt') }}:</strong> {{ session.round_question.prompt }}</p>
+
+      <ng-container *ngIf="showLieControls">
+        <label>{{ copy('player.lie_label') }} <input [(ngModel)]="lieText" [disabled]="loading || !canSubmitLie" /></label>
+        <button (click)="submitLie()" [disabled]="loading || !canSubmitLie">{{ copy('player.submit_lie') }}</button>
+        <button *ngIf="submitError?.kind === 'lie'" (click)="submitLie()" [disabled]="loading || !canSubmitLie">{{ copy('player.retry_lie_submit') }}</button>
+      </ng-container>
+
+      <ng-container *ngIf="showGuessControls">
+        <div class="answers" *ngIf="session.round_question?.answers?.length">
+          <button
+            type="button"
+            *ngFor="let answer of session.round_question?.answers"
+            (click)="selectedGuess = answer.text"
+            [class.active]="selectedGuess === answer.text"
+            [disabled]="loading || !canSubmitGuess"
+          >
+            {{ answer.text }}
+          </button>
+        </div>
+
+        <button (click)="submitGuess()" [disabled]="loading || !canSubmitGuess || !selectedGuess">{{ copy('player.submit_guess') }}</button>
+        <button *ngIf="submitError?.kind === 'guess'" (click)="submitGuess()" [disabled]="loading || !canSubmitGuess">{{ copy('player.retry_guess_submit') }}</button>
+      </ng-container>
+
+      <div class="panel" *ngIf="showRevealPanel">
+        <h3>Reveal</h3>
+        <p><strong>Korrekt svar:</strong> {{ session.reveal.correct_answer }}</p>
+        <p><strong>Spørgsmål:</strong> {{ session.reveal.prompt }}</p>
+        <div *ngIf="session.reveal.lies.length">
+          <strong>Løgne</strong>
+          <ul>
+            <li *ngFor="let lie of session.reveal.lies">{{ lie.nickname }} løj: {{ lie.text }}</li>
+          </ul>
+        </div>
+        <div *ngIf="session.reveal.guesses.length">
+          <strong>Gæt</strong>
+          <ul>
+            <li *ngFor="let guess of session.reveal.guesses">
+              {{ guess.nickname }} valgte {{ guess.selected_text }}
+              <span *ngIf="guess.is_correct">· korrekt</span>
+              <span *ngIf="!guess.is_correct && guess.fooled_player_nickname">· narret af {{ guess.fooled_player_nickname }}</span>
+              <span *ngIf="!guess.is_correct && !guess.fooled_player_nickname">· forkert</span>
+            </li>
+          </ul>
+        </div>
+      </div>
+
+      <div *ngIf="showFinalLeaderboard && finalLeaderboard.length">
+        <h3>{{ copy('player.final_leaderboard') }}</h3>
+        <ol>
+          <li *ngFor="let entry of finalLeaderboard">{{ entry.nickname }}: {{ entry.score }}</li>
+        </ol>
+      </div>
+    </div>
+
+    <p *ngIf="error" class="error">{{ error }}</p>
+    <p *ngIf="submitError" class="error">{{ submitError.message }}</p>
+
+    <div class="panel" *ngIf="error || submitError">
+      <button type="button" (click)="retryReconnect()" [disabled]="loading">{{ copy('common.retry') }}</button>
+      <button type="button" (click)="returnToJoin()" [disabled]="loading">{{ copy('common.back_to_join') }}</button>
+    </div>
+  `,
+})
+export class PlayerShellComponent implements OnInit, OnDestroy {
+  locale = resolvePreferredLocale();
+  readonly clientHasNoAudioOutput = clientHasNoAudioOutput;
+
+  sessionCode = '';
+  nickname = '';
+  playerId = 0;
+  sessionToken = '';
+  lieText = '';
+  selectedGuess = '';
+  loading = false;
+  error = '';
+  submitError: { kind: 'lie' | 'guess'; message: string } | null = null;
+  session: SessionDetail | null = null;
+  finalLeaderboard: Array<{ id: number; nickname: string; score: number }> = [];
+  connectionState: ConnectionState = 'online';
+  loadingTransition: LoadingTransition = null;
+
+  private readonly sessionContextStore = createSessionContextStore(resolveLocalStorage());
+  private readonly controller = createVerticalSliceController(createApiClient(), this.sessionContextStore);
+  private reconnectTimer: ReturnType<typeof setTimeout> | null = null;
+  private stateSyncTimer: ReturnType<typeof setTimeout> | null = null;
+  private unsubscribeLocale: (() => void) | null = null;
+  private restoreAudioGuard: (() => void) | null = null;
+
+  constructor() {
+    if (typeof navigator !== 'undefined' && !navigator.onLine) {
+      this.connectionState = 'offline';
+    }
+
+    if (typeof window !== 'undefined') {
+      window.addEventListener('online', this.handleOnline);
+      window.addEventListener('offline', this.handleOffline);
+    }
+  }
+
+  ngOnInit(): void {
+    this.unsubscribeLocale = subscribeToLocaleChanges((locale) => {
+      this.locale = locale;
+    });
+    this.installSecondaryDeviceAudioGuard();
+
+    const hashRoute = window.location.hash.replace(/^#\/?/, '');
+    const match = hashRoute.match(/^player(?:\/[^/]+)?(?:\/([^/?#]+))?/i);
+    const codeFromRoute = match?.[1] ?? '';
+
+    const persistedContext = this.sessionContextStore.get();
+    if (persistedContext) {
+      this.playerId = persistedContext.playerId;
+      this.sessionToken = persistedContext.token;
+    }
+
+    const candidate = codeFromRoute || persistedContext?.sessionCode || '';
+    if (!candidate) {
+      return;
+    }
+
+    this.sessionCode = this.normalizeCode(candidate);
+    void this.refreshSession();
+  }
+
+  ngOnDestroy(): void {
+    if (typeof window !== 'undefined') {
+      window.removeEventListener('online', this.handleOnline);
+      window.removeEventListener('offline', this.handleOffline);
+    }
+    this.clearReconnectTimer();
+    this.clearStateSyncTimer();
+    this.unsubscribeLocale?.();
+    this.unsubscribeLocale = null;
+    this.restoreAudioGuard?.();
+    this.restoreAudioGuard = null;
+  }
+
+  get gameplayPhase(): string | null {
+    return deriveGameplayPhase(this.session as any);
+  }
+
+  get canSubmitLie(): boolean {
+    return isPlayerGameplayActionAllowed(this.session as any, 'submitLie');
+  }
+
+  get canSubmitGuess(): boolean {
+    return isPlayerGameplayActionAllowed(this.session as any, 'submitGuess');
+  }
+
+  get showRevealPanel(): boolean {
+    return Boolean(this.session?.reveal && (this.gameplayPhase === 'reveal' || this.gameplayPhase === 'scoreboard'));
+  }
+
+  private readonly handleOnline = (): void => {
+    this.connectionState = 'reconnecting';
+    void this.retryReconnect();
+  };
+
+  private readonly handleOffline = (): void => {
+    this.connectionState = 'offline';
+    this.clearReconnectTimer();
+    this.clearStateSyncTimer();
+  };
+
+  private clearReconnectTimer(): void {
+    if (this.reconnectTimer) {
+      clearTimeout(this.reconnectTimer);
+      this.reconnectTimer = null;
+    }
+  }
+
+  private clearStateSyncTimer(): void {
+    if (this.stateSyncTimer) {
+      clearTimeout(this.stateSyncTimer);
+      this.stateSyncTimer = null;
+    }
+  }
+
+  private installSecondaryDeviceAudioGuard(): void {
+    if (!this.clientHasNoAudioOutput || typeof window === 'undefined') {
+      return;
+    }
+
+    this.silenceExistingMediaElements();
+
+    const mediaPrototype = (window as Window & { HTMLMediaElement?: { prototype?: MediaPrototypeWithGuardState } }).HTMLMediaElement
+      ?.prototype;
+
+    if (!mediaPrototype || typeof mediaPrototype.play !== 'function') {
+      return;
+    }
+
+    const guardState = mediaPrototype.__wppSecondaryDeviceAudioGuard__;
+    if (guardState) {
+      guardState.installs += 1;
+    } else {
+      const originalPlay = mediaPrototype.play;
+      mediaPrototype.play = function mediaGuardedPlay(this: GuardableMediaElement): Promise<void> {
+        this.muted = true;
+        this.defaultMuted = true;
+        if (typeof this.volume === 'number') {
+          this.volume = 0;
+        }
+        this.pause?.();
+        return Promise.resolve();
+      };
+      mediaPrototype.__wppSecondaryDeviceAudioGuard__ = {
+        originalPlay,
+        installs: 1,
+      };
+    }
+
+    this.restoreAudioGuard = () => {
+      const currentState = mediaPrototype.__wppSecondaryDeviceAudioGuard__;
+      if (!currentState) {
+        return;
+      }
+
+      currentState.installs -= 1;
+      if (currentState.installs <= 0) {
+        mediaPrototype.play = currentState.originalPlay;
+        delete mediaPrototype.__wppSecondaryDeviceAudioGuard__;
+      }
+    };
+  }
+
+
+  private silenceExistingMediaElements(): void {
+    if (typeof document === 'undefined' || typeof document.querySelectorAll !== 'function') {
+      return;
+    }
+
+    const activeElements = document.querySelectorAll('audio,video') as
+      | NodeListOf<HTMLMediaElement>
+      | GuardableMediaElement[]
+      | undefined;
+
+    if (!activeElements || typeof (activeElements as { forEach?: unknown }).forEach !== 'function') {
+      return;
+    }
+
+    activeElements.forEach((element) => {
+      element.muted = true;
+      element.defaultMuted = true;
+      if (typeof element.volume === 'number') {
+        element.volume = 0;
+      }
+      element.pause?.();
+    });
+  }
+
+  private scheduleStateSync(): void {
+    this.clearStateSyncTimer();
+
+    if (!this.sessionCode.trim() || this.connectionState !== 'online' || !this.session) {
+      return;
+    }
+
+    if (this.session.session.status === 'finished') {
+      return;
+    }
+
+    this.stateSyncTimer = setTimeout(() => {
+      this.stateSyncTimer = null;
+      if (this.loading || this.connectionState !== 'online') {
+        this.scheduleStateSync();
+        return;
+      }
+      void this.refreshSession();
+    }, 3000);
+  }
+
+  get showJoinControls(): boolean {
+    if (!this.session) {
+      return true;
+    }
+    return Boolean(this.session?.phase_view_model?.player?.can_join && !this.playerId && !this.sessionToken);
+  }
+
+  get showLieControls(): boolean {
+    return Boolean(this.session?.phase_view_model?.player?.can_submit_lie);
+  }
+
+  get showGuessControls(): boolean {
+    return Boolean(this.session?.phase_view_model?.player?.can_submit_guess);
+  }
+
+  get showFinalLeaderboard(): boolean {
+    return Boolean(this.session?.phase_view_model?.player?.can_view_final_result);
+  }
+
+  get loadingMessage(): string {
+    switch (this.loadingTransition) {
+      case 'join':
+        return this.copy('player.loading_join');
+      case 'submit-lie':
+        return this.copy('player.loading_submit_lie');
+      case 'submit-guess':
+        return this.copy('player.loading_submit_guess');
+      case 'refresh':
+      default:
+        return this.copy('player.loading_refresh');
+    }
+  }
+
+  copy(key: string): string {
+    return t(key, this.locale);
+  }
+
+  private normalizeCode(value: string): string {
+    return value.trim().toUpperCase();
+  }
+
+  private toMessage(error: unknown): string {
+    if (error instanceof Error && error.message) {
+      return error.message;
+    }
+    return this.copy('common.unknown_error');
+  }
+
+  private markOnline(): void {
+    this.connectionState = 'online';
+    this.clearReconnectTimer();
+    this.scheduleStateSync();
+  }
+
+  private markConnectionIssue(error: unknown): void {
+    this.clearStateSyncTimer();
+
+    if (typeof navigator !== 'undefined' && !navigator.onLine) {
+      this.connectionState = 'offline';
+      return;
+    }
+
+    const message = this.toMessage(error).toLowerCase();
+    if (
+      message.includes('fetch') ||
+      message.includes('network') ||
+      message.includes('failed to') ||
+      message.includes('could not load lobby status') ||
+      message.includes('session refresh failed')
+    ) {
+      this.connectionState = 'reconnecting';
+      this.scheduleReconnect();
+    }
+  }
+
+  private scheduleReconnect(): void {
+    if (this.reconnectTimer || !this.sessionCode.trim()) {
+      return;
+    }
+
+    this.reconnectTimer = setTimeout(() => {
+      this.reconnectTimer = null;
+      void this.retryReconnect();
+    }, 2000);
+  }
+
+  async retryReconnect(): Promise<void> {
+    if (!this.sessionCode.trim() || this.loading) {
+      return;
+    }
+
+    await this.refreshSession();
+  }
+
+  returnToJoin(): void {
+    this.loadingTransition = null;
+    this.clearReconnectTimer();
+    this.clearStateSyncTimer();
+    this.connectionState = typeof navigator !== 'undefined' && !navigator.onLine ? 'offline' : 'online';
+    this.session = null;
+    this.finalLeaderboard = [];
+    this.selectedGuess = '';
+    this.lieText = '';
+    this.submitError = null;
+    this.error = '';
+    this.playerId = 0;
+    this.sessionToken = '';
+    this.sessionContextStore.clear();
+  }
+
+  private syncFinalLeaderboard(): void {
+    if (!this.session || this.session.session.status !== 'finished') {
+      this.finalLeaderboard = [];
+      return;
+    }
+
+    this.finalLeaderboard = [...this.session.players].sort((a, b) => {
+      if (b.score !== a.score) {
+        return b.score - a.score;
+      }
+      return a.nickname.localeCompare(b.nickname);
+    });
+  }
+
+  private syncRouteFromSession(): void {
+    if (!this.session) {
+      return;
+    }
+
+    const phase = this.gameplayPhase ?? this.session.session.status ?? 'lobby';
+    const code = this.normalizeCode(this.session.session.code || this.sessionCode);
+    if (!code) {
+      return;
+    }
+
+    const targetPath = `#/player/${encodeURIComponent(phase)}/${encodeURIComponent(code)}`;
+    if (typeof window === 'undefined' || window.location.hash === targetPath) {
+      return;
+    }
+
+    window.history.replaceState(window.history.state, '', targetPath);
+  }
+
+  private async request<T>(path: string, method: 'GET' | 'POST', payload?: unknown): Promise<T> {
+    const response = await fetch(path, {
+      method,
+      headers: {
+        Accept: 'application/json',
+        ...(payload === undefined ? {} : { 'Content-Type': 'application/json' }),
+      },
+      ...(payload === undefined ? {} : { body: JSON.stringify(payload) }),
+      credentials: 'same-origin',
+    });
+
+    const body = await response.json().catch(() => ({}));
+    if (!response.ok) {
+      throw new Error((body as { error?: string }).error ?? `HTTP ${response.status}`);
+    }
+
+    return body as T;
+  }
+
+  async refreshSession(): Promise<void> {
+    this.loading = true;
+    this.loadingTransition = 'refresh';
+    this.error = '';
+    try {
+      const state = await this.controller.hydrateLobby(this.sessionCode);
+      if (!state.session || state.errorMessage) {
+        throw new Error(state.errorMessage ?? this.copy('common.unknown_error'));
+      }
+      this.session = state.session as SessionDetail;
+      this.sessionCode = this.session.session.code;
+      if (this.session.session.status !== 'guess') {
+        this.selectedGuess = '';
+      }
+      this.syncFinalLeaderboard();
+      this.syncRouteFromSession();
+      this.markOnline();
+    } catch (error) {
+      this.error = `${this.copy('player.session_refresh_failed')}: ${this.toMessage(error)}`;
+      this.markConnectionIssue(error);
+    } finally {
+      this.loading = false;
+      this.loadingTransition = null;
+    }
+  }
+
+  async joinSession(): Promise<void> {
+    this.loading = true;
+    this.loadingTransition = 'join';
+    this.error = '';
+    try {
+      const state = await this.controller.joinLobby(this.sessionCode, this.nickname);
+      if (!state.session || state.errorMessage) {
+        throw new Error(state.errorMessage ?? this.copy('common.unknown_error'));
+      }
+      this.session = state.session as SessionDetail;
+      this.sessionCode = this.session.session.code;
+
+      const sessionContext = this.sessionContextStore.get();
+      this.playerId = sessionContext?.playerId ?? 0;
+      this.sessionToken = sessionContext?.token ?? '';
+      if (this.session.session.status !== 'guess') {
+        this.selectedGuess = '';
+      }
+      this.syncFinalLeaderboard();
+      this.syncRouteFromSession();
+      this.markOnline();
+    } catch (error) {
+      this.error = `${this.copy('player.join_failed')}: ${this.toMessage(error)}`;
+      this.markConnectionIssue(error);
+    } finally {
+      this.loading = false;
+      this.loadingTransition = null;
+    }
+  }
+
+  async submitLie(): Promise<void> {
+    if (!this.session?.round_question?.id || !this.canSubmitLie) {
+      return;
+    }
+    this.loading = true;
+    this.loadingTransition = 'submit-lie';
+    this.submitError = null;
+    try {
+      await this.request(
+        `/lobby/sessions/${encodeURIComponent(this.normalizeCode(this.sessionCode))}/questions/${this.session.round_question.id}/lies/submit`,
+        'POST',
+        {
+          player_id: this.playerId,
+          session_token: this.sessionToken,
+          text: this.lieText,
+        }
+      );
+      await this.refreshSession();
+      this.markOnline();
+    } catch (error) {
+      this.submitError = { kind: 'lie', message: `${this.copy('player.lie_submit_failed')}: ${this.toMessage(error)}` };
+      this.markConnectionIssue(error);
+    } finally {
+      this.loading = false;
+      this.loadingTransition = null;
+    }
+  }
+
+  async submitGuess(): Promise<void> {
+    if (!this.session?.round_question?.id || !this.selectedGuess || !this.canSubmitGuess) {
+      return;
+    }
+    this.loading = true;
+    this.loadingTransition = 'submit-guess';
+    this.submitError = null;
+    try {
+      await this.request(
+        `/lobby/sessions/${encodeURIComponent(this.normalizeCode(this.sessionCode))}/questions/${this.session.round_question.id}/guesses/submit`,
+        'POST',
+        {
+          player_id: this.playerId,
+          session_token: this.sessionToken,
+          selected_text: this.selectedGuess,
+        }
+      );
+      await this.refreshSession();
+      this.markOnline();
+    } catch (error) {
+      this.submitError = { kind: 'guess', message: `${this.copy('player.guess_submit_failed')}: ${this.toMessage(error)}` };
+      this.markConnectionIssue(error);
+    } finally {
+      this.loading = false;
+      this.loadingTransition = null;
+    }
+  }
+}

frontend/angular/src/app/gameplay-phase-machine.spec.ts

@@ -0,0 +1,96 @@
+import { describe, expect, it } from 'vitest';
+
+import { deriveGameplayPhase, transitionGameplayPhase } from '../../../src/spa/gameplay-phase-machine';
+
+describe('gameplay phase machine sync guards', () => {
+  it('keeps explicit scoreboard status as scoreboard phase', () => {
+    const phase = deriveGameplayPhase({
+      session: {
+        code: 'ABCD12',
+        status: 'scoreboard',
+        host_id: 1,
+        current_round: 1,
+        players_count: 2,
+      },
+      round_question: null,
+      players: [],
+      phase_view_model: {
+        status: 'scoreboard',
+        round_number: 1,
+        players_count: 2,
+        constraints: {
+          min_players_to_start: 2,
+          max_players_mvp: 8,
+          min_players_reached: true,
+          max_players_allowed: true,
+        },
+        host: {
+          can_start_round: false,
+          can_show_question: false,
+          can_mix_answers: false,
+          can_calculate_scores: false,
+          can_reveal_scoreboard: false,
+          can_start_next_round: true,
+          can_finish_game: true,
+        },
+        player: {
+          can_join: false,
+          can_submit_lie: false,
+          can_submit_guess: false,
+          can_view_final_result: false,
+        },
+      },
+    });
+
+    expect(phase).toBe('scoreboard');
+  });
+
+  it('maps finished status to scoreboard phase fallback', () => {
+    const phase = deriveGameplayPhase({
+      session: {
+        code: 'ABCD12',
+        status: 'finished',
+        host_id: 1,
+        current_round: 1,
+        players_count: 2,
+      },
+      round_question: null,
+      players: [],
+      phase_view_model: {
+        status: 'finished',
+        round_number: 1,
+        players_count: 2,
+        constraints: {
+          min_players_to_start: 2,
+          max_players_mvp: 8,
+          min_players_reached: true,
+          max_players_allowed: true,
+        },
+        host: {
+          can_start_round: false,
+          can_show_question: false,
+          can_mix_answers: false,
+          can_calculate_scores: false,
+          can_reveal_scoreboard: false,
+          can_start_next_round: false,
+          can_finish_game: false,
+        },
+        player: {
+          can_join: false,
+          can_submit_lie: false,
+          can_submit_guess: false,
+          can_view_final_result: true,
+        },
+      },
+    });
+
+    expect(phase).toBe('scoreboard');
+  });
+
+  it('transitions reveal -> scoreboard on SCOREBOARD_READY', () => {
+    expect(transitionGameplayPhase('reveal', 'SCOREBOARD_READY')).toEqual({
+      phase: 'scoreboard',
+      changed: true,
+    });
+  });
+});

frontend/angular/src/app/i18n-mvp-flow-smoke.spec.ts

@@ -0,0 +1,87 @@
+import { afterEach, describe, expect, it, vi } from 'vitest';
+
+import { HostShellComponent } from './features/host/host-shell.component';
+import { PlayerShellComponent } from './features/player/player-shell.component';
+import { setPreferredLocale } from './lobby-i18n';
+
+function stubShellGlobals(initialLocale: string) {
+  vi.stubGlobal('window', {
+    location: { hash: '', search: '' },
+    history: { state: null, replaceState: vi.fn() },
+    localStorage: { getItem: vi.fn().mockReturnValue(initialLocale), setItem: vi.fn(), removeItem: vi.fn() },
+    sessionStorage: { getItem: vi.fn().mockReturnValue(null), setItem: vi.fn(), removeItem: vi.fn() },
+    addEventListener: vi.fn(),
+    removeEventListener: vi.fn(),
+  });
+  vi.stubGlobal('navigator', { language: `${initialLocale}-US`, onLine: true });
+}
+
+describe('i18n MVP flow smoke (host/player + audio policy)', () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+    vi.unstubAllGlobals();
+  });
+
+  it.each([
+    {
+      locale: 'en',
+      hostRefresh: 'Refresh',
+      hostStartRound: 'Start round',
+      playerSubmitGuess: 'Submit guess',
+    },
+    {
+      locale: 'da',
+      hostRefresh: 'Opdatér',
+      hostStartRound: 'Start runde',
+      playerSubmitGuess: 'Send gæt',
+    },
+  ])('resolves one host/player locale run for $locale', ({ locale, hostRefresh, hostStartRound, playerSubmitGuess }) => {
+    stubShellGlobals(locale);
+
+    const host = new HostShellComponent();
+    const player = new PlayerShellComponent();
+    host.ngOnInit();
+    player.ngOnInit();
+    setPreferredLocale(locale);
+
+    expect(host.copy('common.refresh')).toBe(hostRefresh);
+    expect(host.copy('game.host.start_round')).toBe(hostStartRound);
+    expect(player.copy('game.player.submit_guess')).toBe(playerSubmitGuess);
+
+    player.ngOnDestroy();
+    host.ngOnDestroy();
+  });
+
+  it('keeps audio routing primary-only by guarding player playback without muting the host path', async () => {
+    const originalPlay = vi.fn().mockRejectedValue(new Error('primary host playback'));
+    const mediaPrototype = { play: originalPlay };
+
+    vi.stubGlobal('window', {
+      location: { hash: '', search: '' },
+      history: { state: null, replaceState: vi.fn() },
+      localStorage: { getItem: vi.fn().mockReturnValue('en'), setItem: vi.fn(), removeItem: vi.fn() },
+      sessionStorage: { getItem: vi.fn().mockReturnValue(null), setItem: vi.fn(), removeItem: vi.fn() },
+      addEventListener: vi.fn(),
+      removeEventListener: vi.fn(),
+      HTMLMediaElement: { prototype: mediaPrototype },
+    });
+    vi.stubGlobal('navigator', { language: 'en-US', onLine: true });
+    vi.stubGlobal('document', { querySelectorAll: vi.fn().mockReturnValue([]) });
+
+    const host = new HostShellComponent();
+    host.ngOnInit();
+
+    await expect(mediaPrototype.play()).rejects.toThrow('primary host playback');
+
+    const player = new PlayerShellComponent();
+    player.ngOnInit();
+
+    await expect(mediaPrototype.play()).resolves.toBeUndefined();
+
+    player.ngOnDestroy();
+
+    await expect(mediaPrototype.play()).rejects.toThrow('primary host playback');
+
+    host.ngOnDestroy();
+  });
+});

frontend/angular/src/app/lobby-i18n.spec.ts

@@ -0,0 +1,137 @@
+import { afterEach, describe, expect, it, vi } from 'vitest';
+
+type StorageLike = {
+  getItem: (key: string) => string | null;
+  setItem: (key: string, value: string) => void;
+};
+
+function storageMock(initial: Record<string, string> = {}): StorageLike {
+  const data = new Map<string, string>(Object.entries(initial));
+  return {
+    getItem: vi.fn((key: string) => data.get(key) ?? null),
+    setItem: vi.fn((key: string, value: string) => {
+      data.set(key, value);
+    }),
+  };
+}
+
+describe('lobby i18n locale propagation', () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+    vi.unstubAllGlobals();
+    vi.resetModules();
+  });
+
+  it('notifies subscribers immediately and on locale changes', async () => {
+    const localStorage = storageMock({ 'wpp.locale': 'en' });
+    vi.stubGlobal('window', {
+      location: { search: '' },
+      localStorage,
+    });
+    vi.stubGlobal('navigator', { language: 'en-US' });
+
+    const i18n = await import('./lobby-i18n');
+
+    const updates: string[] = [];
+    const unsubscribe = i18n.subscribeToLocaleChanges((locale) => updates.push(locale));
+
+    expect(updates).toEqual(['en']);
+
+    i18n.setPreferredLocale('da');
+    expect(updates).toEqual(['en', 'da']);
+
+    unsubscribe();
+    i18n.setPreferredLocale('en');
+    expect(updates).toEqual(['en', 'da']);
+  });
+
+  it('prefers backend-provided shell locale over browser defaults', async () => {
+    vi.stubGlobal('window', {
+      location: { search: '' },
+      localStorage: storageMock(),
+    });
+    vi.stubGlobal('document', {
+      body: { dataset: { wppLocale: 'da' } },
+      querySelector: vi.fn(() => null),
+    });
+    vi.stubGlobal('navigator', { language: 'en-US' });
+
+    const i18n = await import('./lobby-i18n');
+
+    expect(i18n.resolvePreferredLocale()).toBe('da');
+  });
+
+  it('falls back to default en translation when da key is intentionally missing', async () => {
+    vi.stubGlobal('window', {
+      location: { search: '' },
+      localStorage: storageMock({ 'wpp.locale': 'da' }),
+    });
+    vi.stubGlobal('navigator', { language: 'da-DK' });
+
+    const i18n = await import('./lobby-i18n');
+    const catalogModule = await import('../../../../shared/i18n/lobby.json');
+    const catalog = catalogModule.default as {
+      frontend: {
+        ui: {
+          common: {
+            refresh: {
+              en?: string;
+              da?: string;
+            };
+          };
+        };
+      };
+    };
+
+    const originalDa = catalog.frontend.ui.common.refresh.da;
+    catalog.frontend.ui.common.refresh.da = undefined;
+
+    try {
+      expect(i18n.t('common.refresh', 'da')).toBe(catalog.frontend.ui.common.refresh.en);
+    } finally {
+      catalog.frontend.ui.common.refresh.da = originalDa;
+    }
+  });
+
+  it('resolves baseline shell/game keys from shared namespaces', async () => {
+    vi.stubGlobal('window', {
+      location: { search: '' },
+      localStorage: storageMock({ 'wpp.locale': 'da' }),
+    });
+    vi.stubGlobal('navigator', { language: 'da-DK' });
+
+    const i18n = await import('./lobby-i18n');
+
+    const baselineKeys = [
+      'lobby.shell.title',
+      'lobby.shell.host_nav',
+      'lobby.shell.player_nav',
+      'lobby.shell.language_label',
+      'common.refresh',
+      'common.session_code',
+      'game.host.title',
+      'game.host.start_round',
+      'game.player.title',
+      'game.player.submit_guess',
+    ] as const;
+
+    for (const key of baselineKeys) {
+      const value = i18n.t(key, 'da');
+      expect(value).toBeTypeOf('string');
+      expect(value.length).toBeGreaterThan(0);
+      expect(value).not.toBe(key);
+    }
+  });
+
+  it('exposes primary-only audio routing policy to clients', async () => {
+    vi.stubGlobal('window', {
+      location: { search: '' },
+      localStorage: storageMock({ 'wpp.locale': 'en' }),
+    });
+    vi.stubGlobal('navigator', { language: 'en-US' });
+
+    const i18n = await import('./lobby-i18n');
+
+    expect(i18n.clientHasNoAudioOutput).toBe(true);
+  });
+});

frontend/angular/src/app/lobby-i18n.ts

@@ -0,0 +1,74 @@
+import {
+  DEFAULT_LOCALE,
+  LOBBY_I18N_CATALOG,
+  normalizeLocale,
+  type SupportedLocale,
+  translateCatalogPath,
+} from '../../../shared/i18n/lobby-loader';
+
+let activeLocale: SupportedLocale | null = null;
+const localeSubscribers = new Set<(locale: SupportedLocale) => void>();
+
+export { normalizeLocale };
+
+export function resolvePreferredLocale(): SupportedLocale {
+  if (activeLocale) {
+    return activeLocale;
+  }
+
+  if (typeof window === 'undefined') {
+    activeLocale = DEFAULT_LOCALE;
+    return activeLocale;
+  }
+
+  const rootLocale =
+    typeof document !== 'undefined' ? document.querySelector<HTMLElement>('app-root')?.dataset?.['wppLocale'] : null;
+  const shellLocale = typeof document !== 'undefined' ? document.body?.dataset?.['wppLocale'] : null;
+  const queryLocale = new URLSearchParams(window.location?.search ?? '').get('lang');
+  const storedLocale = window.localStorage?.getItem?.('wpp.locale');
+  const browserLocale = typeof navigator !== 'undefined' ? navigator.language : '';
+
+  activeLocale = normalizeLocale(rootLocale || shellLocale || queryLocale || storedLocale || browserLocale || DEFAULT_LOCALE);
+  return activeLocale;
+}
+
+export function setPreferredLocale(locale: string): SupportedLocale {
+  const normalized = normalizeLocale(locale);
+  activeLocale = normalized;
+  if (typeof window !== 'undefined') {
+    window.localStorage?.setItem?.('wpp.locale', normalized);
+  }
+
+  for (const subscriber of localeSubscribers) {
+    subscriber(normalized);
+  }
+
+  return normalized;
+}
+
+export function subscribeToLocaleChanges(callback: (locale: SupportedLocale) => void): () => void {
+  localeSubscribers.add(callback);
+  callback(resolvePreferredLocale());
+  return () => {
+    localeSubscribers.delete(callback);
+  };
+}
+
+function resolveCatalogPath(key: string): string {
+  if (key.startsWith('lobby.shell.')) {
+    return key.replace(/^lobby\.shell\./, 'app.');
+  }
+  if (key.startsWith('game.host.')) {
+    return key.replace(/^game\.host\./, 'host.');
+  }
+  if (key.startsWith('game.player.')) {
+    return key.replace(/^game\.player\./, 'player.');
+  }
+  return key;
+}
+
+export function t(key: string, locale: string): string {
+  return translateCatalogPath(LOBBY_I18N_CATALOG.frontend.ui as Record<string, unknown>, resolveCatalogPath(key), locale);
+}
+
+export const clientHasNoAudioOutput = Boolean(LOBBY_I18N_CATALOG.frontend.capabilities.client_has_no_audio_output);

frontend/angular/src/app/session-route-context.spec.ts

@@ -0,0 +1,105 @@
+import { afterEach, describe, expect, it, vi } from 'vitest';
+
+import { hostRouteContextResolver, playerRouteContextResolver, resolveSessionCode } from './session-route-context';
+
+type RouteLike = {
+  paramMap: { get: (key: string) => string | null };
+  queryParamMap: { get: (key: string) => string | null };
+};
+
+function route(params: Record<string, string | null>, query: Record<string, string | null> = {}): RouteLike {
+  return {
+    paramMap: { get: (key: string) => params[key] ?? null },
+    queryParamMap: { get: (key: string) => query[key] ?? null },
+  };
+}
+
+function storageMock(initial: Record<string, string> = {}): Storage {
+  const data = new Map<string, string>(Object.entries(initial));
+
+  return {
+    getItem: vi.fn((key: string) => data.get(key) ?? null),
+    setItem: vi.fn((key: string, value: string) => {
+      data.set(key, value);
+    }),
+    removeItem: vi.fn((key: string) => {
+      data.delete(key);
+    }),
+    clear: vi.fn(() => {
+      data.clear();
+    }),
+    key: vi.fn((index: number) => Array.from(data.keys())[index] ?? null),
+    get length() {
+      return data.size;
+    },
+  } as unknown as Storage;
+}
+
+function setWindow(localStorage: Storage, sessionStorage: Storage): void {
+  vi.stubGlobal('window', { localStorage, sessionStorage });
+}
+
+describe('session route context', () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it('resolves player code from persisted session context when route has no code', () => {
+    setWindow(
+      storageMock({ 'wpp.session-context': JSON.stringify({ sessionCode: 'ab12', playerId: 7, token: 'tok' }) }),
+      storageMock()
+    );
+
+    expect(resolveSessionCode(route({}, {}) as never, 'player')).toBe('AB12');
+  });
+
+  it('resolves host code from session query string', () => {
+    setWindow(storageMock(), storageMock());
+
+    expect(resolveSessionCode(route({}, { session: 'qwe9' }) as never, 'host')).toBe('QWE9');
+  });
+
+  it('player resolver emits player id/token when context matches route session', () => {
+    setWindow(
+      storageMock({ 'wpp.session-context': JSON.stringify({ sessionCode: 'AB12', playerId: 5, token: 'tok-5' }) }),
+      storageMock()
+    );
+
+    expect(playerRouteContextResolver(route({ context: 'ab12' }) as never, {} as never)).toEqual({
+      sessionCode: 'AB12',
+      playerId: 5,
+      token: 'tok-5',
+      locale: 'en',
+    });
+  });
+
+  it('host resolver stores normalized host session code for refresh bootstrap', () => {
+    const sessionStorage = storageMock();
+    setWindow(storageMock(), sessionStorage);
+
+    expect(hostRouteContextResolver(route({ context: 'ab12' }) as never, {} as never)).toEqual({
+      sessionCode: 'AB12',
+      playerId: null,
+      token: null,
+      locale: 'en',
+    });
+    expect(sessionStorage.setItem).toHaveBeenCalledWith('wpp.host-session-code', 'AB12');
+  });
+
+  it('resolvers normalize and expose locale from lang query param', () => {
+    setWindow(storageMock(), storageMock());
+
+    expect(hostRouteContextResolver(route({}, { lang: 'da-DK' }) as never, {} as never).locale).toBe('da');
+    expect(playerRouteContextResolver(route({}, { lang: 'EN' }) as never, {} as never).locale).toBe('en');
+  });
+
+  it('does not reset persisted preferred locale when lang query param is absent', () => {
+    const localStorage = storageMock({ 'wpp.locale': 'da' });
+    setWindow(localStorage, storageMock());
+
+    expect(hostRouteContextResolver(route({}, { lang: 'da' }) as never, {} as never).locale).toBe('da');
+    expect(hostRouteContextResolver(route({}, {}) as never, {} as never).locale).toBe('da');
+    expect(localStorage.setItem).toHaveBeenCalledTimes(1);
+    expect(localStorage.setItem).toHaveBeenCalledWith('wpp.locale', 'da');
+  });
+});

frontend/angular/src/app/session-route-context.ts

@@ -0,0 +1,156 @@
+import { inject } from '@angular/core';
+import { type ActivatedRouteSnapshot, type CanActivateFn, type ResolveFn, Router, type UrlTree } from '@angular/router';
+
+import { createSessionContextStore } from '../../../src/spa/session-context-store';
+import { normalizeLocale, resolvePreferredLocale, setPreferredLocale } from './lobby-i18n';
+
+export interface RouteSessionContext {
+  sessionCode: string | null;
+  playerId: number | null;
+  token: string | null;
+  locale: string;
+}
+
+const HOST_STORAGE_KEY = 'wpp.host-session-code';
+
+function normalizeCode(value: string): string {
+  return value.trim().toUpperCase();
+}
+
+function isCodeLike(value: string | null | undefined): value is string {
+  return !!value && /^[A-Za-z0-9]{4,12}$/.test(value.trim());
+}
+
+function hasPlayerSessionContext(sessionCode: string): boolean {
+  const context = createSessionContextStore(window.localStorage).get();
+  if (!context) {
+    return false;
+  }
+
+  return (
+    isCodeLike(context.sessionCode) &&
+    normalizeCode(context.sessionCode) === normalizeCode(sessionCode) &&
+    Number.isInteger(context.playerId) &&
+    context.playerId > 0 &&
+    !!context.token.trim()
+  );
+}
+
+export function resolveSessionCode(route: ActivatedRouteSnapshot, mode: 'host' | 'player'): string | null {
+  const contextParam = route.paramMap.get('context');
+  const queryCode = route.queryParamMap.get('session');
+
+  if (isCodeLike(contextParam)) {
+    return normalizeCode(contextParam);
+  }
+  if (isCodeLike(queryCode)) {
+    return normalizeCode(queryCode);
+  }
+
+  if (mode === 'player') {
+    const persisted = createSessionContextStore(window.localStorage).get()?.sessionCode;
+    if (isCodeLike(persisted)) {
+      return normalizeCode(persisted);
+    }
+    return null;
+  }
+
+  const stored = window.sessionStorage.getItem(HOST_STORAGE_KEY);
+  if (isCodeLike(stored)) {
+    return normalizeCode(stored);
+  }
+
+  return null;
+}
+
+function resolveRouteLocale(route: ActivatedRouteSnapshot): string {
+  const langParam = route.queryParamMap.get('lang');
+  if (langParam !== null) {
+    const locale = normalizeLocale(langParam);
+    setPreferredLocale(locale);
+    return locale;
+  }
+
+  return resolvePreferredLocale();
+}
+
+async function sessionExists(code: string): Promise<boolean> {
+  const response = await fetch(`/lobby/sessions/${encodeURIComponent(code)}`, {
+    method: 'GET',
+    headers: { Accept: 'application/json' },
+    credentials: 'same-origin',
+  });
+
+  return response.ok;
+}
+
+async function requireSessionContext(route: ActivatedRouteSnapshot, mode: 'host' | 'player'): Promise<boolean> {
+  const phase = route.paramMap.get('phase');
+  const code = resolveSessionCode(route, mode);
+
+  if (!phase) {
+    if (mode === 'host' && code) {
+      window.sessionStorage.setItem(HOST_STORAGE_KEY, code);
+    }
+    return true;
+  }
+
+  if (!code) {
+    return false;
+  }
+
+  if (mode === 'player' && !hasPlayerSessionContext(code)) {
+    return false;
+  }
+
+  const ok = await sessionExists(code);
+  if (!ok) {
+    return false;
+  }
+
+  if (mode === 'host') {
+    window.sessionStorage.setItem(HOST_STORAGE_KEY, code);
+  }
+
+  return true;
+}
+
+async function guard(mode: 'host' | 'player', route: ActivatedRouteSnapshot): Promise<boolean | UrlTree> {
+  const router = inject(Router);
+  const allowed = await requireSessionContext(route, mode);
+  if (allowed) {
+    return true;
+  }
+
+  return router.createUrlTree([`/${mode}`]);
+}
+
+export const hostRouteGuard: CanActivateFn = (route) => guard('host', route);
+
+export const playerRouteGuard: CanActivateFn = (route) => guard('player', route);
+
+export const hostRouteContextResolver: ResolveFn<RouteSessionContext> = (route) => {
+  const code = resolveSessionCode(route, 'host');
+  const locale = resolveRouteLocale(route);
+  if (code) {
+    window.sessionStorage.setItem(HOST_STORAGE_KEY, code);
+  }
+  return { sessionCode: code, playerId: null, token: null, locale };
+};
+
+export const playerRouteContextResolver: ResolveFn<RouteSessionContext> = (route) => {
+  const code = resolveSessionCode(route, 'player');
+  const locale = resolveRouteLocale(route);
+  const context = createSessionContextStore(window.localStorage).get();
+
+  if (!code || !context || normalizeCode(context.sessionCode) !== code) {
+    return { sessionCode: code, playerId: null, token: null, locale };
+  }
+
+  return {
+    sessionCode: code,
+    playerId: Number.isInteger(context.playerId) && context.playerId > 0 ? context.playerId : null,
+    token: context.token.trim() || null,
+    locale,
+  };
+};

frontend/angular/src/app/wpp-api-client.spec.ts

@@ -0,0 +1,43 @@
+import { describe, expect, it, vi } from 'vitest';
+
+import { createWppApiClient } from './wpp-api-client';
+
+function jsonResponse(status: number, body: unknown) {
+  return {
+    ok: status >= 200 && status < 300,
+    status,
+    json: vi.fn().mockResolvedValue(body),
+  } as unknown as Response;
+}
+
+describe('WPP Angular API client skeleton', () => {
+  it('normalizes host/player API calls through fetch transport', async () => {
+    const fetchMock = vi
+      .fn()
+      .mockResolvedValueOnce(jsonResponse(200, { session: { code: 'ABCD12', status: 'lobby', host_id: 1, current_round: 1, players_count: 1 }, players: [], round_question: null, phase_view_model: { status: 'lobby', round_number: 1, players_count: 1, constraints: { min_players_to_start: 2, max_players_mvp: 8, min_players_reached: false, max_players_allowed: true }, host: { can_start_round: false, can_show_question: false, can_mix_answers: false, can_calculate_scores: false, can_reveal_scoreboard: false, can_start_next_round: false, can_finish_game: false }, player: { can_join: true, can_submit_lie: false, can_submit_guess: false, can_view_final_result: false } } }))
+      .mockResolvedValueOnce(jsonResponse(201, { player: { id: 1, nickname: 'Luna', session_token: 'tok', score: 0 }, session: { code: 'ABCD12', status: 'lobby' } }));
+
+    const client = createWppApiClient(fetchMock);
+
+    const session = await client.getSession(' abcd12 ');
+    const joined = await client.joinSession({ code: ' abcd12 ', nickname: ' Luna ' });
+
+    expect(session.ok).toBe(true);
+    expect(joined.ok).toBe(true);
+
+    expect(fetchMock).toHaveBeenNthCalledWith(
+      1,
+      '/lobby/sessions/ABCD12',
+      expect.objectContaining({ method: 'GET', credentials: 'same-origin' })
+    );
+    expect(fetchMock).toHaveBeenNthCalledWith(
+      2,
+      '/lobby/sessions/join',
+      expect.objectContaining({
+        method: 'POST',
+        credentials: 'same-origin',
+        body: JSON.stringify({ code: 'ABCD12', nickname: 'Luna' }),
+      })
+    );
+  });
+});

frontend/angular/src/app/wpp-api-client.ts

@@ -0,0 +1,58 @@
+import { InjectionToken } from '@angular/core';
+
+import {
+  createAngularApiClient,
+  type AngularApiClient,
+  type AngularHttpClientLike,
+} from '../../../src/api/angular-client';
+
+export const WPP_API_CLIENT = new InjectionToken<AngularApiClient>('WPP_API_CLIENT');
+
+export interface FetchLike {
+  (input: string, init?: RequestInit): Promise<Response>;
+}
+
+export function createFetchHttpClient(fetchImpl: FetchLike): AngularHttpClientLike {
+  return {
+    async get<T>(url: string): Promise<T> {
+      const response = await fetchImpl(url, {
+        method: 'GET',
+        headers: { Accept: 'application/json' },
+        credentials: 'same-origin',
+      });
+      const payload = await response.json().catch(() => ({}));
+      if (!response.ok) {
+        throw {
+          status: response.status,
+          message: (payload as { error?: string }).error ?? `HTTP ${response.status}`,
+          error: payload,
+        };
+      }
+      return payload as T;
+    },
+    async post<T>(url: string, body: unknown): Promise<T> {
+      const response = await fetchImpl(url, {
+        method: 'POST',
+        headers: {
+          Accept: 'application/json',
+          'Content-Type': 'application/json',
+        },
+        body: JSON.stringify(body),
+        credentials: 'same-origin',
+      });
+      const payload = await response.json().catch(() => ({}));
+      if (!response.ok) {
+        throw {
+          status: response.status,
+          message: (payload as { error?: string }).error ?? `HTTP ${response.status}`,
+          error: payload,
+        };
+      }
+      return payload as T;
+    },
+  };
+}
+
+export function createWppApiClient(fetchImpl: FetchLike = fetch.bind(globalThis)): AngularApiClient {
+  return createAngularApiClient(createFetchHttpClient(fetchImpl));
+}

frontend/angular/src/index.html

@@ -0,0 +1,12 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8" />
+    <title>WPP Angular Shell</title>
+    <base href="/" />
+    <meta name="viewport" content="width=device-width, initial-scale=1" />
+  </head>
+  <body>
+    <app-root></app-root>
+  </body>
+</html>

frontend/angular/src/main.ts

@@ -0,0 +1,7 @@
+import { bootstrapApplication } from '@angular/platform-browser';
+import { AppComponent } from './app/app.component';
+import { appConfig } from './app/app.config';
+
+bootstrapApplication(AppComponent, appConfig).catch((error) => {
+  console.error(error);
+});

frontend/angular/src/styles.css

@@ -0,0 +1,4 @@
+html, body {
+  margin: 0;
+  padding: 0;
+}

frontend/angular/src/test-setup.ts

@@ -0,0 +1 @@
+import '@angular/compiler';

frontend/angular/tsconfig.app.json

@@ -0,0 +1,9 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "outDir": "./out-tsc/app",
+    "types": []
+  },
+  "files": ["src/main.ts"],
+  "include": ["src/**/*.d.ts"]
+}

frontend/angular/tsconfig.json

@@ -0,0 +1,22 @@
+{
+  "compileOnSave": false,
+  "compilerOptions": {
+    "strict": true,
+    "skipLibCheck": true,
+    "isolatedModules": true,
+    "esModuleInterop": true,
+    "sourceMap": true,
+    "declaration": false,
+    "experimentalDecorators": true,
+    "moduleResolution": "bundler",
+    "importHelpers": true,
+    "target": "ES2022",
+    "module": "ES2022",
+    "lib": ["ES2022", "dom"]
+  },
+  "angularCompilerOptions": {
+    "strictInjectionParameters": true,
+    "strictInputAccessModifiers": true,
+    "strictTemplates": true
+  }
+}

frontend/angular/vitest.config.ts

@@ -0,0 +1,8 @@
+import { defineConfig } from 'vitest/config';
+
+export default defineConfig({
+  test: {
+    include: ['src/**/*.spec.ts'],
+    setupFiles: ['src/test-setup.ts'],
+  },
+});

frontend/package.json

@@ -0,0 +1,26 @@
+{
+  "name": "wpp-frontend-api-client-baseline",
+  "private": true,
+  "version": "0.1.0",
+  "type": "module",
+  "scripts": {
+    "test": "vitest run",
+    "build": "tsc --noEmit"
+  },
+  "dependencies": {
+    "@angular/common": "^19.2.0",
+    "@angular/compiler": "^19.2.0",
+    "@angular/core": "^19.2.0",
+    "@angular/forms": "^19.2.0",
+    "@angular/platform-browser": "^19.2.0",
+    "@angular/router": "^19.2.0",
+    "rxjs": "~7.8.0",
+    "tslib": "^2.3.0",
+    "zone.js": "~0.15.0"
+  },
+  "devDependencies": {
+    "@types/node": "^22.13.10",
+    "typescript": "^5.7.3",
+    "vitest": "^2.1.9"
+  }
+}

frontend/shared/i18n/lobby-loader.ts

@@ -0,0 +1,74 @@
+import lobbyCatalog from '../../../shared/i18n/lobby.json';
+
+export type LobbyCatalog = typeof lobbyCatalog;
+export type SupportedLocale = LobbyCatalog['locales']['supported'][number];
+
+export const LOBBY_I18N_CATALOG = lobbyCatalog;
+export const DEFAULT_LOCALE = lobbyCatalog.locales.default as SupportedLocale;
+export const SUPPORTED_LOCALES = lobbyCatalog.locales.supported as readonly SupportedLocale[];
+
+export function normalizeLocale(rawLocale?: string | null): SupportedLocale {
+  const locale = (rawLocale ?? '').trim().toLowerCase().replace(/_/g, '-');
+  if ((SUPPORTED_LOCALES as readonly string[]).includes(locale)) {
+    return locale as SupportedLocale;
+  }
+
+  const shortLocale = locale.split('-')[0] ?? '';
+  if ((SUPPORTED_LOCALES as readonly string[]).includes(shortLocale)) {
+    return shortLocale as SupportedLocale;
+  }
+
+  return DEFAULT_LOCALE;
+}
+
+export function translateCatalogPath(
+  root: Record<string, unknown>,
+  keyPath: string,
+  locale: string,
+  fallback = DEFAULT_LOCALE,
+): string {
+  const normalizedLocale = normalizeLocale(locale);
+  const segments = keyPath.split('.');
+
+  let cursor: unknown = root;
+  for (const segment of segments) {
+    if (!cursor || typeof cursor !== 'object' || !(segment in (cursor as Record<string, unknown>))) {
+      return keyPath;
+    }
+    cursor = (cursor as Record<string, unknown>)[segment];
+  }
+
+  if (!cursor || typeof cursor !== 'object') {
+    return keyPath;
+  }
+
+  const translations = cursor as Record<string, string>;
+  return translations[normalizedLocale] ?? translations[fallback] ?? keyPath;
+}
+
+export function collectLocaleParityIssues(
+  node: unknown,
+  locales: readonly string[] = SUPPORTED_LOCALES,
+  path = '',
+): string[] {
+  if (!node || typeof node !== 'object') {
+    return [];
+  }
+
+  const record = node as Record<string, unknown>;
+  const keys = Object.keys(record);
+  const isTranslationLeaf = keys.length > 0 && locales.every((locale) => locale in record);
+
+  if (isTranslationLeaf) {
+    const issues: string[] = [];
+    for (const locale of locales) {
+      const value = record[locale];
+      if (typeof value !== 'string' || !value.trim()) {
+        issues.push(`${path || '<root>'} missing non-empty '${locale}' translation`);
+      }
+    }
+    return issues;
+  }
+
+  return keys.flatMap((key) => collectLocaleParityIssues(record[key], locales, path ? `${path}.${key}` : key));
+}

frontend/src/api/angular-client.ts

@@ -0,0 +1,262 @@
+import {
+  mapCalculateScoresResponse,
+  mapFinishGameResponse,
+  mapHealthResponse,
+  mapJoinSessionResponse,
+  mapMixAnswersResponse,
+  mapScoreboardResponse,
+  mapSessionDetailResponse,
+  mapShowQuestionResponse,
+  mapStartNextRoundResponse,
+  mapStartRoundResponse,
+  mapSubmitGuessResponse,
+  mapSubmitLieResponse
+} from './mappers';
+import type {
+  ApiFailure,
+  ApiResult,
+  CalculateScoresResponse,
+  FinishGameResponse,
+  HealthResponse,
+  JoinSessionRequest,
+  JoinSessionResponse,
+  MixAnswersResponse,
+  ScoreboardResponse,
+  SessionDetailResponse,
+  ShowQuestionResponse,
+  StartNextRoundResponse,
+  StartRoundRequest,
+  StartRoundResponse,
+  SubmitGuessRequest,
+  SubmitGuessResponse,
+  SubmitLieRequest,
+  SubmitLieResponse
+} from './types';
+
+export interface AngularHttpError {
+  status?: number;
+  message?: string;
+  error?: unknown;
+}
+
+export interface AngularHttpClientLike {
+  get<T>(url: string, options?: { withCredentials?: boolean }): Promise<T>;
+  post<T>(url: string, body: unknown, options?: { withCredentials?: boolean }): Promise<T>;
+}
+
+export interface AngularApiClient {
+  health(): Promise<ApiResult<HealthResponse>>;
+  getSession(code: string): Promise<ApiResult<SessionDetailResponse>>;
+  joinSession(payload: JoinSessionRequest): Promise<ApiResult<JoinSessionResponse>>;
+  startRound(code: string, payload: StartRoundRequest): Promise<ApiResult<StartRoundResponse>>;
+  showQuestion(code: string): Promise<ApiResult<ShowQuestionResponse>>;
+  mixAnswers(code: string, roundQuestionId: number): Promise<ApiResult<MixAnswersResponse>>;
+  calculateScores(code: string, roundQuestionId: number): Promise<ApiResult<CalculateScoresResponse>>;
+  getScoreboard(code: string): Promise<ApiResult<ScoreboardResponse>>;
+  startNextRound(code: string): Promise<ApiResult<StartNextRoundResponse>>;
+  finishGame(code: string): Promise<ApiResult<FinishGameResponse>>;
+  submitLie(code: string, roundQuestionId: number, payload: SubmitLieRequest): Promise<ApiResult<SubmitLieResponse>>;
+  submitGuess(
+    code: string,
+    roundQuestionId: number,
+    payload: SubmitGuessRequest
+  ): Promise<ApiResult<SubmitGuessResponse>>;
+}
+
+function toFailure(error: unknown): ApiFailure {
+  const candidate = (error ?? {}) as AngularHttpError;
+  const status = typeof candidate.status === 'number' ? candidate.status : 0;
+  const payload = candidate.error;
+
+  if (status === 0) {
+    return {
+      kind: 'network',
+      status: 0,
+      message: candidate.message ?? 'Network error while contacting API'
+    };
+  }
+
+  return {
+    kind: 'http',
+    status,
+    message: candidate.message ?? `HTTP ${status}`,
+    ...(payload === undefined ? {} : { payload })
+  };
+}
+
+function normalizeCode(code: string): string {
+  return code.trim().toUpperCase();
+}
+
+function normalizeBaseUrl(baseUrl: string): string {
+  return baseUrl.endsWith('/') ? baseUrl.slice(0, -1) : baseUrl;
+}
+
+function buildUrl(baseUrl: string, path: string): string {
+  return `${normalizeBaseUrl(baseUrl)}${path}`;
+}
+
+async function wrap<T>(call: () => Promise<unknown>, mapper: (payload: unknown) => T): Promise<ApiResult<T>> {
+  let payload: unknown;
+  try {
+    payload = await call();
+  } catch (error: unknown) {
+    return {
+      ok: false,
+      status: typeof (error as AngularHttpError)?.status === 'number' ? (error as AngularHttpError).status! : 0,
+      error: toFailure(error)
+    };
+  }
+
+  try {
+    return { ok: true, status: 200, data: mapper(payload) };
+  } catch (error: unknown) {
+    return {
+      ok: false,
+      status: 200,
+      error: {
+        kind: 'parse',
+        status: 200,
+        message: error instanceof Error ? error.message : 'Invalid API response contract',
+        payload
+      }
+    };
+  }
+}
+
+export function createAngularApiClient(http: AngularHttpClientLike, baseUrl = ''): AngularApiClient {
+  return {
+    health: () =>
+      wrap(() => http.get<HealthResponse>(buildUrl(baseUrl, '/healthz'), { withCredentials: true }), mapHealthResponse),
+    getSession: (code: string) =>
+      wrap(
+        () =>
+          http.get<SessionDetailResponse>(buildUrl(baseUrl, `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}`), {
+            withCredentials: true
+          }),
+        mapSessionDetailResponse
+      ),
+    joinSession: (payload: JoinSessionRequest) =>
+      wrap(
+        () =>
+          http.post<JoinSessionResponse>(
+            buildUrl(baseUrl, '/lobby/sessions/join'),
+            {
+              code: normalizeCode(payload.code),
+              nickname: payload.nickname.trim()
+            },
+            { withCredentials: true }
+          ),
+        mapJoinSessionResponse
+      ),
+    startRound: (code: string, payload: StartRoundRequest) =>
+      wrap(
+        () =>
+          http.post<StartRoundResponse>(
+            buildUrl(baseUrl, `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/rounds/start`),
+            payload,
+            { withCredentials: true }
+          ),
+        mapStartRoundResponse
+      ),
+    showQuestion: (code: string) =>
+      wrap(
+        () =>
+          http.post<ShowQuestionResponse>(
+            buildUrl(baseUrl, `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/questions/show`),
+            {},
+            { withCredentials: true }
+          ),
+        mapShowQuestionResponse
+      ),
+    mixAnswers: (code: string, roundQuestionId: number) =>
+      wrap(
+        () =>
+          http.post<MixAnswersResponse>(
+            buildUrl(
+              baseUrl,
+              `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/questions/${roundQuestionId}/answers/mix`
+            ),
+            {},
+            { withCredentials: true }
+          ),
+        mapMixAnswersResponse
+      ),
+    calculateScores: (code: string, roundQuestionId: number) =>
+      wrap(
+        () =>
+          http.post<CalculateScoresResponse>(
+            buildUrl(
+              baseUrl,
+              `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/questions/${roundQuestionId}/scores/calculate`
+            ),
+            {},
+            { withCredentials: true }
+          ),
+        mapCalculateScoresResponse
+      ),
+    getScoreboard: (code: string) =>
+      wrap(
+        () =>
+          http.get<ScoreboardResponse>(
+            buildUrl(baseUrl, `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/scoreboard`),
+            { withCredentials: true }
+          ),
+        mapScoreboardResponse
+      ),
+    startNextRound: (code: string) =>
+      wrap(
+        () =>
+          http.post<StartNextRoundResponse>(
+            buildUrl(baseUrl, `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/rounds/next`),
+            {},
+            { withCredentials: true }
+          ),
+        mapStartNextRoundResponse
+      ),
+    finishGame: (code: string) =>
+      wrap(
+        () =>
+          http.post<FinishGameResponse>(
+            buildUrl(baseUrl, `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/finish`),
+            {},
+            { withCredentials: true }
+          ),
+        mapFinishGameResponse
+      ),
+    submitLie: (code: string, roundQuestionId: number, payload: SubmitLieRequest) =>
+      wrap(
+        () =>
+          http.post<SubmitLieResponse>(
+            buildUrl(
+              baseUrl,
+              `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/questions/${roundQuestionId}/lies/submit`
+            ),
+            {
+              player_id: payload.player_id,
+              session_token: payload.session_token,
+              text: payload.text
+            },
+            { withCredentials: true }
+          ),
+        mapSubmitLieResponse
+      ),
+    submitGuess: (code: string, roundQuestionId: number, payload: SubmitGuessRequest) =>
+      wrap(
+        () =>
+          http.post<SubmitGuessResponse>(
+            buildUrl(
+              baseUrl,
+              `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/questions/${roundQuestionId}/guesses/submit`
+            ),
+            {
+              player_id: payload.player_id,
+              session_token: payload.session_token,
+              selected_text: payload.selected_text
+            },
+            { withCredentials: true }
+          ),
+        mapSubmitGuessResponse
+      )
+  };
+}

frontend/src/api/client.ts

@@ -0,0 +1,198 @@
+import {
+  mapCalculateScoresResponse,
+  mapFinishGameResponse,
+  mapHealthResponse,
+  mapJoinSessionResponse,
+  mapMixAnswersResponse,
+  mapScoreboardResponse,
+  mapSessionDetailResponse,
+  mapShowQuestionResponse,
+  mapStartNextRoundResponse,
+  mapStartRoundResponse,
+  mapSubmitGuessResponse,
+  mapSubmitLieResponse
+} from './mappers';
+import type {
+  ApiResult,
+  CalculateScoresResponse,
+  FinishGameResponse,
+  HealthResponse,
+  JoinSessionRequest,
+  JoinSessionResponse,
+  MixAnswersResponse,
+  ScoreboardResponse,
+  SessionDetailResponse,
+  ShowQuestionResponse,
+  StartNextRoundResponse,
+  StartRoundRequest,
+  StartRoundResponse,
+  SubmitGuessRequest,
+  SubmitGuessResponse,
+  SubmitLieRequest,
+  SubmitLieResponse
+} from './types';
+
+export interface ApiClient {
+  health(): Promise<ApiResult<HealthResponse>>;
+  getSession(code: string): Promise<ApiResult<SessionDetailResponse>>;
+  joinSession(payload: JoinSessionRequest): Promise<ApiResult<JoinSessionResponse>>;
+  startRound(code: string, payload: StartRoundRequest): Promise<ApiResult<StartRoundResponse>>;
+  showQuestion(code: string): Promise<ApiResult<ShowQuestionResponse>>;
+  mixAnswers(code: string, roundQuestionId: number): Promise<ApiResult<MixAnswersResponse>>;
+  calculateScores(code: string, roundQuestionId: number): Promise<ApiResult<CalculateScoresResponse>>;
+  getScoreboard(code: string): Promise<ApiResult<ScoreboardResponse>>;
+  startNextRound(code: string): Promise<ApiResult<StartNextRoundResponse>>;
+  finishGame(code: string): Promise<ApiResult<FinishGameResponse>>;
+  submitLie(code: string, roundQuestionId: number, payload: SubmitLieRequest): Promise<ApiResult<SubmitLieResponse>>;
+  submitGuess(code: string, roundQuestionId: number, payload: SubmitGuessRequest): Promise<ApiResult<SubmitGuessResponse>>;
+}
+
+export function createApiClient(baseUrl = '', fetchImpl: typeof fetch = fetch): ApiClient {
+  async function request<T>(
+    path: string,
+    method: 'GET' | 'POST',
+    mapper: (payload: unknown) => T,
+    payload?: unknown
+  ): Promise<ApiResult<T>> {
+    let response: Response;
+    try {
+      response = await fetchImpl(`${baseUrl}${path}`, {
+        method,
+        headers: {
+          Accept: 'application/json',
+          ...(payload === undefined ? {} : { 'Content-Type': 'application/json' })
+        },
+        ...(payload === undefined ? {} : { body: JSON.stringify(payload) })
+      });
+    } catch {
+      return {
+        ok: false,
+        status: 0,
+        error: { kind: 'network', status: 0, message: 'Network error while contacting API' }
+      };
+    }
+
+    let responsePayload: unknown;
+    try {
+      responsePayload = await response.json();
+    } catch {
+      return {
+        ok: false,
+        status: response.status,
+        error: { kind: 'parse', status: response.status, message: 'Invalid JSON response from API' }
+      };
+    }
+
+    if (!response.ok) {
+      return {
+        ok: false,
+        status: response.status,
+        error: {
+          kind: 'http',
+          status: response.status,
+          message: `HTTP ${response.status}`,
+          payload: responsePayload
+        }
+      };
+    }
+
+    try {
+      return { ok: true, status: response.status, data: mapper(responsePayload) };
+    } catch (error) {
+      return {
+        ok: false,
+        status: response.status,
+        error: {
+          kind: 'parse',
+          status: response.status,
+          message: error instanceof Error ? error.message : 'Invalid API response contract',
+          payload: responsePayload
+        }
+      };
+    }
+  }
+
+  const normalizeCode = (value: string): string => value.trim().toUpperCase();
+
+  return {
+    health: () => request<HealthResponse>('/healthz', 'GET', mapHealthResponse),
+    getSession: (code: string) =>
+      request<SessionDetailResponse>(
+        `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}`,
+        'GET',
+        mapSessionDetailResponse
+      ),
+    joinSession: (payload: JoinSessionRequest) =>
+      request<JoinSessionResponse>(
+        '/lobby/sessions/join',
+        'POST',
+        mapJoinSessionResponse,
+        {
+          code: normalizeCode(payload.code),
+          nickname: payload.nickname.trim()
+        }
+      ),
+    startRound: (code: string, payload: StartRoundRequest) =>
+      request<StartRoundResponse>(
+        `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/rounds/start`,
+        'POST',
+        mapStartRoundResponse,
+        payload
+      ),
+    showQuestion: (code: string) =>
+      request<ShowQuestionResponse>(
+        `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/questions/show`,
+        'POST',
+        mapShowQuestionResponse,
+        {}
+      ),
+    mixAnswers: (code: string, roundQuestionId: number) =>
+      request<MixAnswersResponse>(
+        `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/questions/${roundQuestionId}/answers/mix`,
+        'POST',
+        mapMixAnswersResponse,
+        {}
+      ),
+    calculateScores: (code: string, roundQuestionId: number) =>
+      request<CalculateScoresResponse>(
+        `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/questions/${roundQuestionId}/scores/calculate`,
+        'POST',
+        mapCalculateScoresResponse,
+        {}
+      ),
+    getScoreboard: (code: string) =>
+      request<ScoreboardResponse>(
+        `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/scoreboard`,
+        'GET',
+        mapScoreboardResponse
+      ),
+    startNextRound: (code: string) =>
+      request<StartNextRoundResponse>(
+        `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/rounds/next`,
+        'POST',
+        mapStartNextRoundResponse,
+        {}
+      ),
+    finishGame: (code: string) =>
+      request<FinishGameResponse>(
+        `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/finish`,
+        'POST',
+        mapFinishGameResponse,
+        {}
+      ),
+    submitLie: (code: string, roundQuestionId: number, payload: SubmitLieRequest) =>
+      request<SubmitLieResponse>(
+        `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/questions/${roundQuestionId}/lies/submit`,
+        'POST',
+        mapSubmitLieResponse,
+        payload
+      ),
+    submitGuess: (code: string, roundQuestionId: number, payload: SubmitGuessRequest) =>
+      request<SubmitGuessResponse>(
+        `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/questions/${roundQuestionId}/guesses/submit`,
+        'POST',
+        mapSubmitGuessResponse,
+        payload
+      )
+  };
+}

frontend/src/api/mappers.ts

@@ -0,0 +1,434 @@
+import type {
+  CalculateScoresResponse,
+  FinishGameResponse,
+  HealthResponse,
+  JoinSessionResponse,
+  MixAnswersResponse,
+  ScoreboardResponse,
+  SessionDetailResponse,
+  ShowQuestionResponse,
+  StartNextRoundResponse,
+  StartRoundResponse,
+  SubmitGuessResponse,
+  SubmitLieResponse
+} from './types';
+
+function isRecord(value: unknown): value is Record<string, unknown> {
+  return typeof value === 'object' && value !== null;
+}
+
+function isBoolean(value: unknown): value is boolean {
+  return typeof value === 'boolean';
+}
+
+function isNumber(value: unknown): value is number {
+  return typeof value === 'number' && Number.isFinite(value);
+}
+
+function isString(value: unknown): value is string {
+  return typeof value === 'string';
+}
+
+function asRecord(value: unknown, path: string): Record<string, unknown> {
+  if (!isRecord(value)) {
+    throw new Error(`Invalid API contract: expected object at ${path}`);
+  }
+  return value;
+}
+
+function readString(record: Record<string, unknown>, key: string, path: string): string {
+  const value = record[key];
+  if (!isString(value)) {
+    throw new Error(`Invalid API contract: expected string at ${path}.${key}`);
+  }
+  return value;
+}
+
+function readNumber(record: Record<string, unknown>, key: string, path: string): number {
+  const value = record[key];
+  if (!isNumber(value)) {
+    throw new Error(`Invalid API contract: expected number at ${path}.${key}`);
+  }
+  return value;
+}
+
+function readBoolean(record: Record<string, unknown>, key: string, path: string): boolean {
+  const value = record[key];
+  if (!isBoolean(value)) {
+    throw new Error(`Invalid API contract: expected boolean at ${path}.${key}`);
+  }
+  return value;
+}
+
+function readNullableNumber(record: Record<string, unknown>, key: string, path: string): number | null {
+  const value = record[key];
+  if (value === undefined || value === null) {
+    return null;
+  }
+  if (!isNumber(value)) {
+    throw new Error(`Invalid API contract: expected number|null at ${path}.${key}`);
+  }
+  return value;
+}
+
+export function mapHealthResponse(payload: unknown): HealthResponse {
+  const root = asRecord(payload, 'health');
+  return {
+    ok: readBoolean(root, 'ok', 'health'),
+    service: readString(root, 'service', 'health')
+  };
+}
+
+function mapSessionDetail(payload: unknown): SessionDetailResponse {
+  const root = asRecord(payload, 'session_detail');
+  const session = asRecord(root.session, 'session_detail.session');
+  const players = root.players;
+  if (!Array.isArray(players)) {
+    throw new Error('Invalid API contract: expected array at session_detail.players');
+  }
+
+  const roundQuestionRaw = root.round_question;
+  let roundQuestion: SessionDetailResponse['round_question'] = null;
+  if (roundQuestionRaw !== null) {
+    const roundQuestionRecord = asRecord(roundQuestionRaw, 'session_detail.round_question');
+    const answersRaw = roundQuestionRecord.answers;
+    if (!Array.isArray(answersRaw)) {
+      throw new Error('Invalid API contract: expected array at session_detail.round_question.answers');
+    }
+
+    roundQuestion = {
+      id: readNumber(roundQuestionRecord, 'id', 'session_detail.round_question'),
+      round_number: readNumber(roundQuestionRecord, 'round_number', 'session_detail.round_question'),
+      prompt: readString(roundQuestionRecord, 'prompt', 'session_detail.round_question'),
+      shown_at: readString(roundQuestionRecord, 'shown_at', 'session_detail.round_question'),
+      answers: answersRaw.map((answer, index) => {
+        const answerRecord = asRecord(answer, `session_detail.round_question.answers[${index}]`);
+        return { text: readString(answerRecord, 'text', `session_detail.round_question.answers[${index}]`) };
+      })
+    };
+  }
+
+  const phase = asRecord(root.phase_view_model, 'session_detail.phase_view_model');
+  const constraints = asRecord(phase.constraints, 'session_detail.phase_view_model.constraints');
+  const host = asRecord(phase.host, 'session_detail.phase_view_model.host');
+  const player = asRecord(phase.player, 'session_detail.phase_view_model.player');
+
+  const revealRaw = root.reveal;
+  let reveal: SessionDetailResponse['reveal'] = null;
+  if (revealRaw !== null && revealRaw !== undefined) {
+    const revealRecord = asRecord(revealRaw, 'session_detail.reveal');
+    const liesRaw = revealRecord.lies;
+    const guessesRaw = revealRecord.guesses;
+    if (!Array.isArray(liesRaw)) {
+      throw new Error('Invalid API contract: expected array at session_detail.reveal.lies');
+    }
+    if (!Array.isArray(guessesRaw)) {
+      throw new Error('Invalid API contract: expected array at session_detail.reveal.guesses');
+    }
+
+    reveal = {
+      round_question_id: readNumber(revealRecord, 'round_question_id', 'session_detail.reveal'),
+      round_number: readNumber(revealRecord, 'round_number', 'session_detail.reveal'),
+      prompt: readString(revealRecord, 'prompt', 'session_detail.reveal'),
+      correct_answer: readString(revealRecord, 'correct_answer', 'session_detail.reveal'),
+      lies: liesRaw.map((lie, index) => {
+        const record = asRecord(lie, `session_detail.reveal.lies[${index}]`);
+        return {
+          player_id: readNumber(record, 'player_id', `session_detail.reveal.lies[${index}]`),
+          nickname: readString(record, 'nickname', `session_detail.reveal.lies[${index}]`),
+          text: readString(record, 'text', `session_detail.reveal.lies[${index}]`),
+          created_at: readString(record, 'created_at', `session_detail.reveal.lies[${index}]`)
+        };
+      }),
+      guesses: guessesRaw.map((guess, index) => {
+        const path = `session_detail.reveal.guesses[${index}]`;
+        const record = asRecord(guess, path);
+        const fooledPlayerId = readNullableNumber(record, 'fooled_player_id', path);
+        const fooledPlayerNickname = record.fooled_player_nickname;
+        if (fooledPlayerId === null) {
+          if (fooledPlayerNickname !== undefined) {
+            throw new Error(`Invalid API contract: expected ${path}.fooled_player_nickname to be omitted when fooled_player_id is null`);
+          }
+        } else if (!isString(fooledPlayerNickname)) {
+          throw new Error(`Invalid API contract: expected string at ${path}.fooled_player_nickname when fooled_player_id is set`);
+        }
+        return {
+          player_id: readNumber(record, 'player_id', path),
+          nickname: readString(record, 'nickname', path),
+          selected_text: readString(record, 'selected_text', path),
+          is_correct: readBoolean(record, 'is_correct', path),
+          fooled_player_id: fooledPlayerId,
+          ...(fooledPlayerNickname === undefined ? {} : { fooled_player_nickname: fooledPlayerNickname }),
+          created_at: readString(record, 'created_at', path)
+        };
+      })
+    };
+  }
+
+  return {
+    session: {
+      code: readString(session, 'code', 'session_detail.session'),
+      status: readString(session, 'status', 'session_detail.session'),
+      host_id: (() => {
+        const hostId = session.host_id;
+        if (hostId === null) {
+          return null;
+        }
+        if (!isNumber(hostId)) {
+          throw new Error('Invalid API contract: expected number|null at session_detail.session.host_id');
+        }
+        return hostId;
+      })(),
+      current_round: readNumber(session, 'current_round', 'session_detail.session'),
+      players_count: readNumber(session, 'players_count', 'session_detail.session')
+    },
+    players: players.map((item, index) => {
+      const record = asRecord(item, `session_detail.players[${index}]`);
+      return {
+        id: readNumber(record, 'id', `session_detail.players[${index}]`),
+        nickname: readString(record, 'nickname', `session_detail.players[${index}]`),
+        score: readNumber(record, 'score', `session_detail.players[${index}]`),
+        is_connected: readBoolean(record, 'is_connected', `session_detail.players[${index}]`)
+      };
+    }),
+    round_question: roundQuestion,
+    reveal,
+    phase_view_model: {
+      status: readString(phase, 'status', 'session_detail.phase_view_model'),
+      current_phase: typeof phase.current_phase === 'string' ? phase.current_phase : undefined,
+      round_number: readNumber(phase, 'round_number', 'session_detail.phase_view_model'),
+      players_count: readNumber(phase, 'players_count', 'session_detail.phase_view_model'),
+      constraints: {
+        min_players_to_start: readNumber(constraints, 'min_players_to_start', 'session_detail.phase_view_model.constraints'),
+        max_players_mvp: readNumber(constraints, 'max_players_mvp', 'session_detail.phase_view_model.constraints'),
+        min_players_reached: readBoolean(constraints, 'min_players_reached', 'session_detail.phase_view_model.constraints'),
+        max_players_allowed: readBoolean(constraints, 'max_players_allowed', 'session_detail.phase_view_model.constraints')
+      },
+      readiness:
+        phase.readiness && typeof phase.readiness === 'object'
+          ? {
+              question_ready:
+                typeof (phase.readiness as Record<string, unknown>).question_ready === 'boolean'
+                  ? ((phase.readiness as Record<string, unknown>).question_ready as boolean)
+                  : undefined,
+              scoreboard_ready:
+                typeof (phase.readiness as Record<string, unknown>).scoreboard_ready === 'boolean'
+                  ? ((phase.readiness as Record<string, unknown>).scoreboard_ready as boolean)
+                  : undefined,
+            }
+          : undefined,
+      host: {
+        can_start_round: readBoolean(host, 'can_start_round', 'session_detail.phase_view_model.host'),
+        can_show_question: readBoolean(host, 'can_show_question', 'session_detail.phase_view_model.host'),
+        can_mix_answers: readBoolean(host, 'can_mix_answers', 'session_detail.phase_view_model.host'),
+        can_calculate_scores: readBoolean(host, 'can_calculate_scores', 'session_detail.phase_view_model.host'),
+        can_reveal_scoreboard: readBoolean(host, 'can_reveal_scoreboard', 'session_detail.phase_view_model.host'),
+        can_start_next_round: readBoolean(host, 'can_start_next_round', 'session_detail.phase_view_model.host'),
+        can_finish_game: readBoolean(host, 'can_finish_game', 'session_detail.phase_view_model.host')
+      },
+      player: {
+        can_join: readBoolean(player, 'can_join', 'session_detail.phase_view_model.player'),
+        can_submit_lie: readBoolean(player, 'can_submit_lie', 'session_detail.phase_view_model.player'),
+        can_submit_guess: readBoolean(player, 'can_submit_guess', 'session_detail.phase_view_model.player'),
+        can_view_final_result: readBoolean(player, 'can_view_final_result', 'session_detail.phase_view_model.player')
+      }
+    }
+  };
+}
+
+export function mapSessionDetailResponse(payload: unknown): SessionDetailResponse {
+  return mapSessionDetail(payload);
+}
+
+export function mapJoinSessionResponse(payload: unknown): JoinSessionResponse {
+  const root = asRecord(payload, 'join_session');
+  const player = asRecord(root.player, 'join_session.player');
+  const session = asRecord(root.session, 'join_session.session');
+
+  return {
+    player: {
+      id: readNumber(player, 'id', 'join_session.player'),
+      nickname: readString(player, 'nickname', 'join_session.player'),
+      session_token: readString(player, 'session_token', 'join_session.player'),
+      score: readNumber(player, 'score', 'join_session.player')
+    },
+    session: {
+      code: readString(session, 'code', 'join_session.session'),
+      status: readString(session, 'status', 'join_session.session')
+    }
+  };
+}
+
+export function mapStartRoundResponse(payload: unknown): StartRoundResponse {
+  const root = asRecord(payload, 'start_round');
+  const session = asRecord(root.session, 'start_round.session');
+  const round = asRecord(root.round, 'start_round.round');
+  const category = asRecord(round.category, 'start_round.round.category');
+
+  return {
+    session: {
+      code: readString(session, 'code', 'start_round.session'),
+      status: readString(session, 'status', 'start_round.session'),
+      current_round: readNumber(session, 'current_round', 'start_round.session')
+    },
+    round: {
+      number: readNumber(round, 'number', 'start_round.round'),
+      category: {
+        slug: readString(category, 'slug', 'start_round.round.category'),
+        name: readString(category, 'name', 'start_round.round.category')
+      }
+    }
+  };
+}
+
+function mapLeaderboardEntry(payload: unknown, path: string): { id: number; nickname: string; score: number } {
+  const record = asRecord(payload, path);
+  return {
+    id: readNumber(record, 'id', path),
+    nickname: readString(record, 'nickname', path),
+    score: readNumber(record, 'score', path)
+  };
+}
+
+function mapSessionState(payload: unknown, path: string): { code: string; status: string; current_round: number } {
+  const session = asRecord(payload, path);
+  return {
+    code: readString(session, 'code', path),
+    status: readString(session, 'status', path),
+    current_round: readNumber(session, 'current_round', path)
+  };
+}
+
+export function mapShowQuestionResponse(payload: unknown): ShowQuestionResponse {
+  const root = asRecord(payload, 'show_question');
+  const roundQuestion = asRecord(root.round_question, 'show_question.round_question');
+  const config = asRecord(root.config, 'show_question.config');
+
+  return {
+    round_question: {
+      id: readNumber(roundQuestion, 'id', 'show_question.round_question'),
+      prompt: readString(roundQuestion, 'prompt', 'show_question.round_question'),
+      round_number: readNumber(roundQuestion, 'round_number', 'show_question.round_question'),
+      shown_at: readString(roundQuestion, 'shown_at', 'show_question.round_question'),
+      lie_deadline_at: readString(roundQuestion, 'lie_deadline_at', 'show_question.round_question')
+    },
+    config: {
+      lie_seconds: readNumber(config, 'lie_seconds', 'show_question.config')
+    }
+  };
+}
+
+export function mapMixAnswersResponse(payload: unknown): MixAnswersResponse {
+  const root = asRecord(payload, 'mix_answers');
+  const roundQuestion = asRecord(root.round_question, 'mix_answers.round_question');
+  const answersRaw = root.answers;
+  if (!Array.isArray(answersRaw)) {
+    throw new Error('Invalid API contract: expected array at mix_answers.answers');
+  }
+
+  return {
+    session: mapSessionState(root.session, 'mix_answers.session'),
+    round_question: {
+      id: readNumber(roundQuestion, 'id', 'mix_answers.round_question'),
+      round_number: readNumber(roundQuestion, 'round_number', 'mix_answers.round_question')
+    },
+    answers: answersRaw.map((answer, index) => {
+      const record = asRecord(answer, `mix_answers.answers[${index}]`);
+      return { text: readString(record, 'text', `mix_answers.answers[${index}]`) };
+    })
+  };
+}
+
+export function mapCalculateScoresResponse(payload: unknown): CalculateScoresResponse {
+  const root = asRecord(payload, 'calculate_scores');
+  const roundQuestion = asRecord(root.round_question, 'calculate_scores.round_question');
+  const leaderboardRaw = root.leaderboard;
+  if (!Array.isArray(leaderboardRaw)) {
+    throw new Error('Invalid API contract: expected array at calculate_scores.leaderboard');
+  }
+
+  return {
+    session: mapSessionState(root.session, 'calculate_scores.session'),
+    round_question: {
+      id: readNumber(roundQuestion, 'id', 'calculate_scores.round_question'),
+      round_number: readNumber(roundQuestion, 'round_number', 'calculate_scores.round_question')
+    },
+    events_created: readNumber(root, 'events_created', 'calculate_scores'),
+    leaderboard: leaderboardRaw.map((entry, index) => mapLeaderboardEntry(entry, `calculate_scores.leaderboard[${index}]`))
+  };
+}
+
+export function mapScoreboardResponse(payload: unknown): ScoreboardResponse {
+  const root = asRecord(payload, 'scoreboard');
+  const leaderboardRaw = root.leaderboard;
+  if (!Array.isArray(leaderboardRaw)) {
+    throw new Error('Invalid API contract: expected array at scoreboard.leaderboard');
+  }
+
+  return {
+    session: mapSessionState(root.session, 'scoreboard.session'),
+    leaderboard: leaderboardRaw.map((entry, index) => mapLeaderboardEntry(entry, `scoreboard.leaderboard[${index}]`))
+  };
+}
+
+export function mapStartNextRoundResponse(payload: unknown): StartNextRoundResponse {
+  const root = asRecord(payload, 'start_next_round');
+  return { session: mapSessionState(root.session, 'start_next_round.session') };
+}
+
+export function mapFinishGameResponse(payload: unknown): FinishGameResponse {
+  const root = asRecord(payload, 'finish_game');
+  const leaderboardRaw = root.leaderboard;
+  if (!Array.isArray(leaderboardRaw)) {
+    throw new Error('Invalid API contract: expected array at finish_game.leaderboard');
+  }
+
+  const winnerRaw = root.winner;
+
+  return {
+    session: mapSessionState(root.session, 'finish_game.session'),
+    winner: winnerRaw === null ? null : mapLeaderboardEntry(winnerRaw, 'finish_game.winner'),
+    leaderboard: leaderboardRaw.map((entry, index) => mapLeaderboardEntry(entry, `finish_game.leaderboard[${index}]`))
+  };
+}
+
+export function mapSubmitLieResponse(payload: unknown): SubmitLieResponse {
+  const root = asRecord(payload, 'submit_lie');
+  const lie = asRecord(root.lie, 'submit_lie.lie');
+  const window = asRecord(root.window, 'submit_lie.window');
+
+  return {
+    lie: {
+      id: readNumber(lie, 'id', 'submit_lie.lie'),
+      player_id: readNumber(lie, 'player_id', 'submit_lie.lie'),
+      round_question_id: readNumber(lie, 'round_question_id', 'submit_lie.lie'),
+      text: readString(lie, 'text', 'submit_lie.lie'),
+      created_at: readString(lie, 'created_at', 'submit_lie.lie')
+    },
+    window: {
+      lie_deadline_at: readString(window, 'lie_deadline_at', 'submit_lie.window')
+    }
+  };
+}
+
+export function mapSubmitGuessResponse(payload: unknown): SubmitGuessResponse {
+  const root = asRecord(payload, 'submit_guess');
+  const guess = asRecord(root.guess, 'submit_guess.guess');
+  const window = asRecord(root.window, 'submit_guess.window');
+  const fooledPlayerId = readNullableNumber(guess, 'fooled_player_id', 'submit_guess.guess');
+
+  return {
+    guess: {
+      id: readNumber(guess, 'id', 'submit_guess.guess'),
+      player_id: readNumber(guess, 'player_id', 'submit_guess.guess'),
+      round_question_id: readNumber(guess, 'round_question_id', 'submit_guess.guess'),
+      selected_text: readString(guess, 'selected_text', 'submit_guess.guess'),
+      is_correct: readBoolean(guess, 'is_correct', 'submit_guess.guess'),
+      fooled_player_id: fooledPlayerId,
+      created_at: readString(guess, 'created_at', 'submit_guess.guess')
+    },
+    window: {
+      guess_deadline_at: readString(window, 'guess_deadline_at', 'submit_guess.window')
+    }
+  };
+}

frontend/src/api/types.ts

@@ -0,0 +1,254 @@
+export interface HealthResponse {
+  ok: boolean;
+  service: string;
+}
+
+export interface SessionSummary {
+  code: string;
+  status: string;
+  host_id: number | null;
+  current_round: number;
+  players_count: number;
+}
+
+export interface SessionPlayer {
+  id: number;
+  nickname: string;
+  score: number;
+  is_connected: boolean;
+}
+
+export interface SessionAnswer {
+  text: string;
+}
+
+export interface SessionRoundQuestion {
+  id: number;
+  round_number: number;
+  prompt: string;
+  shown_at: string;
+  answers: SessionAnswer[];
+}
+
+export interface PhaseViewModel {
+  status: string;
+  current_phase?: string;
+  round_number: number;
+  players_count: number;
+  constraints: {
+    min_players_to_start: number;
+    max_players_mvp: number;
+    min_players_reached: boolean;
+    max_players_allowed: boolean;
+  };
+  readiness?: {
+    question_ready?: boolean;
+    scoreboard_ready?: boolean;
+  };
+  host: {
+    can_start_round: boolean;
+    can_show_question: boolean;
+    can_mix_answers: boolean;
+    can_calculate_scores: boolean;
+    can_reveal_scoreboard: boolean;
+    can_start_next_round: boolean;
+    can_finish_game: boolean;
+  };
+  player: {
+    can_join: boolean;
+    can_submit_lie: boolean;
+    can_submit_guess: boolean;
+    can_view_final_result: boolean;
+  };
+}
+
+export interface RevealLie {
+  player_id: number;
+  nickname: string;
+  text: string;
+  created_at: string;
+}
+
+export interface RevealGuess {
+  player_id: number;
+  nickname: string;
+  selected_text: string;
+  is_correct: boolean;
+  fooled_player_id: number | null;
+  fooled_player_nickname?: string;
+  created_at: string;
+}
+
+export interface RevealPayload {
+  round_question_id: number;
+  round_number: number;
+  prompt: string;
+  correct_answer: string;
+  lies: RevealLie[];
+  guesses: RevealGuess[];
+}
+
+export interface SessionDetailResponse {
+  session: SessionSummary;
+  players: SessionPlayer[];
+  round_question: SessionRoundQuestion | null;
+  reveal: RevealPayload | null;
+  phase_view_model: PhaseViewModel;
+}
+
+export interface JoinSessionRequest {
+  code: string;
+  nickname: string;
+}
+
+export interface JoinSessionResponse {
+  player: {
+    id: number;
+    nickname: string;
+    session_token: string;
+    score: number;
+  };
+  session: {
+    code: string;
+    status: string;
+  };
+}
+
+export interface StartRoundRequest {
+  category_slug: string;
+}
+
+export interface StartRoundResponse {
+  session: {
+    code: string;
+    status: string;
+    current_round: number;
+  };
+  round: {
+    number: number;
+    category: {
+      slug: string;
+      name: string;
+    };
+  };
+}
+
+export interface ShowQuestionResponse {
+  round_question: {
+    id: number;
+    prompt: string;
+    round_number: number;
+    shown_at: string;
+    lie_deadline_at: string;
+  };
+  config: {
+    lie_seconds: number;
+  };
+}
+
+export interface MixAnswersResponse {
+  session: {
+    code: string;
+    status: string;
+    current_round: number;
+  };
+  round_question: {
+    id: number;
+    round_number: number;
+  };
+  answers: Array<{ text: string }>;
+}
+
+export interface CalculateScoresResponse {
+  session: {
+    code: string;
+    status: string;
+    current_round: number;
+  };
+  round_question: {
+    id: number;
+    round_number: number;
+  };
+  events_created: number;
+  leaderboard: Array<{ id: number; nickname: string; score: number }>;
+}
+
+export interface ScoreboardResponse {
+  session: {
+    code: string;
+    status: string;
+    current_round: number;
+  };
+  leaderboard: Array<{ id: number; nickname: string; score: number }>;
+}
+
+export interface StartNextRoundResponse {
+  session: {
+    code: string;
+    status: string;
+    current_round: number;
+  };
+}
+
+export interface FinishGameResponse {
+  session: {
+    code: string;
+    status: string;
+    current_round: number;
+  };
+  winner: { id: number; nickname: string; score: number } | null;
+  leaderboard: Array<{ id: number; nickname: string; score: number }>;
+}
+
+export interface SubmitLieRequest {
+  player_id: number;
+  session_token: string;
+  text: string;
+}
+
+export interface SubmitLieResponse {
+  lie: {
+    id: number;
+    player_id: number;
+    round_question_id: number;
+    text: string;
+    created_at: string;
+  };
+  window: {
+    lie_deadline_at: string;
+  };
+}
+
+export interface SubmitGuessRequest {
+  player_id: number;
+  session_token: string;
+  selected_text: string;
+}
+
+export interface SubmitGuessResponse {
+  guess: {
+    id: number;
+    player_id: number;
+    round_question_id: number;
+    selected_text: string;
+    is_correct: boolean;
+    fooled_player_id: number | null;
+    created_at: string;
+  };
+  window: {
+    guess_deadline_at: string;
+  };
+}
+
+export type ApiErrorKind = 'network' | 'http' | 'parse';
+
+export interface ApiFailure {
+  kind: ApiErrorKind;
+  message: string;
+  status: number;
+  payload?: unknown;
+}
+
+export type ApiResult<T> =
+  | { ok: true; status: number; data: T }
+  | { ok: false; status: number; error: ApiFailure };

frontend/src/spa/gameplay-phase-machine.ts

@@ -0,0 +1,122 @@
+import type { PhaseViewModel, SessionDetailResponse } from '../api/types';
+
+export type GameplayPhase = 'lie' | 'guess' | 'reveal' | 'scoreboard';
+export type HostGameplayAction =
+  | 'startRound'
+  | 'showQuestion'
+  | 'mixAnswers'
+  | 'calculateScores'
+  | 'loadScoreboard'
+  | 'startNextRound'
+  | 'finishGame';
+export type PlayerGameplayAction = 'join' | 'submitLie' | 'submitGuess' | 'viewFinalResult';
+
+export type GameplayPhaseEvent =
+  | 'LIES_LOCKED'
+  | 'GUESSES_LOCKED'
+  | 'SCOREBOARD_READY'
+  | 'NEXT_ROUND';
+
+export interface GameplayTransitionResult {
+  phase: GameplayPhase;
+  changed: boolean;
+}
+
+const TRANSITIONS: Record<GameplayPhase, Partial<Record<GameplayPhaseEvent, GameplayPhase>>> = {
+  lie: {
+    LIES_LOCKED: 'guess'
+  },
+  guess: {
+    GUESSES_LOCKED: 'reveal'
+  },
+  reveal: {
+    SCOREBOARD_READY: 'scoreboard'
+  },
+  scoreboard: {
+    NEXT_ROUND: 'lie'
+  }
+};
+
+export function transitionGameplayPhase(phase: GameplayPhase, event: GameplayPhaseEvent): GameplayTransitionResult {
+  const next = TRANSITIONS[phase][event] ?? phase;
+  return {
+    phase: next,
+    changed: next !== phase
+  };
+}
+
+export function allowedGameplayEvents(phase: GameplayPhase): GameplayPhaseEvent[] {
+  return Object.keys(TRANSITIONS[phase]) as GameplayPhaseEvent[];
+}
+
+function derivePhaseFromStatus(status: string | null | undefined): GameplayPhase | null {
+  if (!status) {
+    return null;
+  }
+
+  if (status === 'lie' || status === 'guess' || status === 'reveal' || status === 'scoreboard') {
+    return status;
+  }
+
+  if (status === 'finished') {
+    return 'scoreboard';
+  }
+
+  return null;
+}
+
+function deriveCanonicalPhaseStatus(phaseViewModel: PhaseViewModel | null | undefined): string | null {
+  if (!phaseViewModel) {
+    return null;
+  }
+
+  const currentPhase = (phaseViewModel as PhaseViewModel & { current_phase?: string }).current_phase;
+  return currentPhase ?? phaseViewModel.status ?? null;
+}
+
+export function deriveGameplayPhase(session: SessionDetailResponse | null): GameplayPhase | null {
+  const canonicalStatus = deriveCanonicalPhaseStatus(session?.phase_view_model);
+  return derivePhaseFromStatus(canonicalStatus ?? session?.session.status);
+}
+
+export function isHostGameplayActionAllowed(session: SessionDetailResponse | null, action: HostGameplayAction): boolean {
+  if (!session) {
+    return action === 'startRound';
+  }
+
+  const host = session.phase_view_model?.host;
+  switch (action) {
+    case 'startRound':
+      return Boolean(host?.can_start_round ?? false);
+    case 'showQuestion':
+      return Boolean(host?.can_show_question ?? false);
+    case 'mixAnswers':
+      return Boolean(host?.can_mix_answers ?? false);
+    case 'calculateScores':
+      return Boolean(host?.can_calculate_scores ?? false);
+    case 'loadScoreboard':
+      return Boolean(host?.can_reveal_scoreboard ?? false);
+    case 'startNextRound':
+      return Boolean(host?.can_start_next_round ?? false);
+    case 'finishGame':
+      return Boolean(host?.can_finish_game ?? false);
+  }
+}
+
+export function isPlayerGameplayActionAllowed(session: SessionDetailResponse | null, action: PlayerGameplayAction): boolean {
+  if (!session) {
+    return action === 'join';
+  }
+
+  const player = session.phase_view_model?.player;
+  switch (action) {
+    case 'join':
+      return Boolean(player?.can_join ?? false);
+    case 'submitLie':
+      return Boolean(player?.can_submit_lie ?? false);
+    case 'submitGuess':
+      return Boolean(player?.can_submit_guess ?? false);
+    case 'viewFinalResult':
+      return Boolean(player?.can_view_final_result ?? false);
+  }
+}

frontend/src/spa/lobby-i18n.ts

@@ -0,0 +1,48 @@
+import { DEFAULT_LOCALE, LOBBY_I18N_CATALOG, normalizeLocale } from '../../shared/i18n/lobby-loader';
+
+const frontendErrors = LOBBY_I18N_CATALOG.frontend.errors;
+const backendToFrontendErrorKeys = LOBBY_I18N_CATALOG.contract.backend_to_frontend_error_keys as Record<
+  string,
+  keyof typeof frontendErrors
+>;
+
+type FrontendErrorKey = keyof typeof frontendErrors;
+
+function isFrontendErrorKey(value: string): value is FrontendErrorKey {
+  return value in frontendErrors;
+}
+
+export function lobbyMessage(key: FrontendErrorKey, locale?: string): string {
+  const resolvedLocale = normalizeLocale(locale);
+  const translations = frontendErrors[key] as Record<string, string>;
+
+  if (translations[resolvedLocale]) {
+    return translations[resolvedLocale];
+  }
+  if (translations[DEFAULT_LOCALE]) {
+    return translations[DEFAULT_LOCALE];
+  }
+
+  return key;
+}
+
+export function lobbyMessageFromApiPayload(payload: unknown, fallbackKey: FrontendErrorKey, locale?: string): string {
+  if (!payload || typeof payload !== 'object') {
+    return lobbyMessage(fallbackKey, locale);
+  }
+
+  const record = payload as Record<string, unknown>;
+  const code = typeof record.error_code === 'string' ? record.error_code : '';
+  const payloadLocale = typeof record.locale === 'string' ? record.locale : locale;
+  const mappedKey = code ? backendToFrontendErrorKeys[code] : undefined;
+
+  if (mappedKey && isFrontendErrorKey(mappedKey)) {
+    return lobbyMessage(mappedKey, payloadLocale);
+  }
+
+  if (isFrontendErrorKey(code)) {
+    return lobbyMessage(code, payloadLocale);
+  }
+
+  return lobbyMessage(fallbackKey, payloadLocale);
+}

frontend/src/spa/session-context-store.ts

@@ -0,0 +1,123 @@
+export interface SessionContext {
+  sessionCode: string;
+  playerId: number;
+  token: string;
+}
+
+export interface SessionContextInput {
+  sessionCode: string;
+  playerId: number;
+  token: string;
+}
+
+export interface SessionContextStore {
+  get(): SessionContext | null;
+  set(input: SessionContextInput): SessionContext;
+  clear(): void;
+}
+
+export interface StorageLike {
+  getItem(key: string): string | null;
+  setItem(key: string, value: string): void;
+  removeItem(key: string): void;
+}
+
+const DEFAULT_STORAGE_KEY = 'wpp.session-context';
+
+function normalizeSessionCode(value: string): string {
+  return value.trim().toUpperCase();
+}
+
+function normalizeToken(value: string): string {
+  return value.trim();
+}
+
+function toContext(input: SessionContextInput): SessionContext {
+  const sessionCode = normalizeSessionCode(input.sessionCode);
+  const token = normalizeToken(input.token);
+
+  if (!sessionCode) {
+    throw new Error('sessionCode is required');
+  }
+  if (!Number.isInteger(input.playerId) || input.playerId <= 0) {
+    throw new Error('playerId must be a positive integer');
+  }
+  if (!token) {
+    throw new Error('token is required');
+  }
+
+  return {
+    sessionCode,
+    playerId: input.playerId,
+    token
+  };
+}
+
+function safeParse(raw: string): SessionContext | null {
+  try {
+    const data = JSON.parse(raw) as Partial<SessionContextInput>;
+    if (typeof data.sessionCode !== 'string' || typeof data.playerId !== 'number' || typeof data.token !== 'string') {
+      return null;
+    }
+    return toContext({
+      sessionCode: data.sessionCode,
+      playerId: data.playerId,
+      token: data.token
+    });
+  } catch {
+    return null;
+  }
+}
+
+export function createSessionContextStore(storage?: StorageLike, storageKey = DEFAULT_STORAGE_KEY): SessionContextStore {
+  let current: SessionContext | null = null;
+
+  function getFromStorage(): SessionContext | null {
+    if (!storage) {
+      return null;
+    }
+
+    const raw = storage.getItem(storageKey);
+    if (!raw) {
+      return null;
+    }
+
+    const parsed = safeParse(raw);
+    if (!parsed) {
+      storage.removeItem(storageKey);
+      return null;
+    }
+
+    return parsed;
+  }
+
+  return {
+    get(): SessionContext | null {
+      if (current) {
+        return { ...current };
+      }
+
+      const fromStorage = getFromStorage();
+      if (fromStorage) {
+        current = fromStorage;
+        return { ...current };
+      }
+
+      return null;
+    },
+    set(input: SessionContextInput): SessionContext {
+      const normalized = toContext(input);
+      current = normalized;
+      if (storage) {
+        storage.setItem(storageKey, JSON.stringify(normalized));
+      }
+      return { ...normalized };
+    },
+    clear(): void {
+      current = null;
+      if (storage) {
+        storage.removeItem(storageKey);
+      }
+    }
+  };
+}

frontend/src/spa/vertical-slice.ts

@@ -0,0 +1,146 @@
+import type { ApiClient } from '../api/client';
+import type { SessionDetailResponse } from '../api/types';
+import {
+  createSessionContextStore,
+  type SessionContext,
+  type SessionContextInput,
+  type SessionContextStore as PersistedSessionContextStore
+} from './session-context-store';
+import { deriveGameplayPhase, type GameplayPhase } from './gameplay-phase-machine';
+import { lobbyMessage, lobbyMessageFromApiPayload } from './lobby-i18n';
+
+export type AsyncState = 'idle' | 'loading' | 'success' | 'error';
+
+export type SessionContextStore = Pick<PersistedSessionContextStore, 'get' | 'set'>;
+
+export interface VerticalSliceState {
+  sessionCode: string;
+  session: SessionDetailResponse | null;
+  gameplayPhase: GameplayPhase | null;
+  joinState: AsyncState;
+  startRoundState: AsyncState;
+  loadingSession: boolean;
+  errorMessage: string | null;
+}
+
+export interface VerticalSliceController {
+  getState(): VerticalSliceState;
+  hydrateLobby(sessionCode: string): Promise<VerticalSliceState>;
+  joinLobby(sessionCode: string, nickname: string): Promise<VerticalSliceState>;
+  startRound(sessionCode: string, categorySlug: string): Promise<VerticalSliceState>;
+}
+
+export function createVerticalSliceController(
+  api: ApiClient,
+  sessionContextStore: SessionContextStore = createSessionContextStore()
+): VerticalSliceController {
+  const persistedContext = sessionContextStore.get();
+
+  const state: VerticalSliceState = {
+    sessionCode: persistedContext?.sessionCode ?? '',
+    session: null,
+    gameplayPhase: null,
+    joinState: 'idle',
+    startRoundState: 'idle',
+    loadingSession: false,
+    errorMessage: null
+  };
+
+  const normalizeCode = (value: string): string => value.trim().toUpperCase();
+
+  async function hydrateLobby(sessionCode: string): Promise<VerticalSliceState> {
+    state.loadingSession = true;
+    state.errorMessage = null;
+
+    const normalizedRequestedCode = normalizeCode(sessionCode);
+    const fallbackCode = normalizeCode(state.sessionCode || persistedContext?.sessionCode || '');
+    state.sessionCode = normalizedRequestedCode || fallbackCode;
+
+    if (!state.sessionCode) {
+      state.loadingSession = false;
+      state.errorMessage = lobbyMessage('session_code_required');
+      return { ...state };
+    }
+
+    const result = await api.getSession(state.sessionCode);
+    state.loadingSession = false;
+
+    if (!result.ok) {
+      state.errorMessage = lobbyMessageFromApiPayload(result.error.payload, 'session_fetch_failed');
+      state.gameplayPhase = null;
+      return { ...state };
+    }
+
+    state.session = result.data;
+    state.gameplayPhase = deriveGameplayPhase(result.data);
+    state.sessionCode = normalizeCode(result.data.session.code);
+
+    if (persistedContext && state.sessionCode === normalizeCode(persistedContext.sessionCode)) {
+      sessionContextStore.set({ ...persistedContext, sessionCode: state.sessionCode });
+    }
+
+    return { ...state };
+  }
+
+  async function joinLobby(sessionCode: string, nickname: string): Promise<VerticalSliceState> {
+    state.joinState = 'loading';
+    state.errorMessage = null;
+
+    const normalizedRequestedCode = normalizeCode(sessionCode);
+    const fallbackCode = normalizeCode(state.sessionCode || persistedContext?.sessionCode || '');
+    const requestCode = normalizedRequestedCode || fallbackCode;
+
+    const join = await api.joinSession({ code: requestCode, nickname });
+    if (!join.ok) {
+      state.joinState = 'error';
+      state.errorMessage = lobbyMessageFromApiPayload(join.error.payload, 'join_failed');
+      return { ...state };
+    }
+
+    state.joinState = 'success';
+    state.sessionCode = normalizeCode(join.data.session.code || requestCode);
+
+    const nextContext: SessionContextInput = {
+      sessionCode: state.sessionCode,
+      playerId: join.data.player.id,
+      token: join.data.player.session_token
+    };
+    sessionContextStore.set(nextContext);
+
+    return hydrateLobby(state.sessionCode);
+  }
+
+  async function startRound(sessionCode: string, categorySlug: string): Promise<VerticalSliceState> {
+    state.startRoundState = 'loading';
+    state.errorMessage = null;
+
+    const normalizedRequestedCode = normalizeCode(sessionCode);
+    const fallbackCode = normalizeCode(state.sessionCode || persistedContext?.sessionCode || '');
+    const codeToUse = normalizedRequestedCode || fallbackCode;
+
+    if (!codeToUse) {
+      state.startRoundState = 'error';
+      state.errorMessage = lobbyMessage('session_code_required');
+      return { ...state };
+    }
+
+    const start = await api.startRound(codeToUse, { category_slug: categorySlug });
+    if (!start.ok) {
+      state.startRoundState = 'error';
+      state.errorMessage = lobbyMessageFromApiPayload(start.error.payload, 'start_round_failed');
+      return { ...state };
+    }
+
+    state.startRoundState = 'success';
+    return hydrateLobby(codeToUse);
+  }
+
+  return {
+    getState: () => ({ ...state }),
+    hydrateLobby,
+    joinLobby,
+    startRound
+  };
+}
+
+export type { SessionContext };

frontend/tests/angular-api-client.test.ts

@@ -0,0 +1,739 @@
+import { describe, expect, it, vi } from 'vitest';
+
+import { createAngularApiClient, type AngularHttpClientLike } from '../src/api/angular-client';
+import { mapSessionDetailResponse, mapSubmitGuessResponse } from '../src/api/mappers';
+
+describe('createAngularApiClient', () => {
+  it('reads health and session detail using Django-compatible endpoints', async () => {
+    const get = vi.fn<AngularHttpClientLike['get']>(async <T>(url: string) => {
+      if (url === '/healthz') {
+        return { ok: true, service: 'partyhub' } as T;
+      }
+
+      if (url === '/lobby/sessions/ABCD12') {
+        return {
+          session: { code: 'ABCD12', status: 'lobby', host_id: 1, current_round: 1, players_count: 2 },
+          players: [
+            { id: 2, nickname: 'Maja', score: 0, is_connected: true },
+            { id: 3, nickname: 'Bo', score: 0, is_connected: false }
+          ],
+          round_question: null,
+          phase_view_model: {
+            status: 'lobby',
+            round_number: 1,
+            players_count: 2,
+            constraints: {
+              min_players_to_start: 2,
+              max_players_mvp: 8,
+              min_players_reached: true,
+              max_players_allowed: true
+            },
+            host: {
+              can_start_round: true,
+              can_show_question: false,
+              can_mix_answers: false,
+              can_calculate_scores: false,
+              can_reveal_scoreboard: false,
+              can_start_next_round: false,
+              can_finish_game: false
+            },
+            player: {
+              can_join: true,
+              can_submit_lie: false,
+              can_submit_guess: false,
+              can_view_final_result: false
+            }
+          }
+        } as T;
+      }
+
+      throw { status: 404, error: { error: 'Not found' } };
+    });
+
+    const post = vi.fn<AngularHttpClientLike['post']>(async <T>(url: string, body: unknown) => {
+      if (url === '/lobby/sessions/join') {
+        expect(body).toEqual({ code: 'ABCD12', nickname: 'Maja' });
+        return {
+          player: { id: 9, nickname: 'Maja', session_token: 'token-1', score: 0 },
+          session: { code: 'ABCD12', status: 'lobby' }
+        } as T;
+      }
+
+      if (url === '/lobby/sessions/ABCD12/rounds/start') {
+        expect(body).toEqual({ category_slug: 'history' });
+        return {
+          session: { code: 'ABCD12', status: 'lie', current_round: 1 },
+          round: { number: 1, category: { slug: 'history', name: 'History' } }
+        } as T;
+      }
+
+      throw { status: 404, error: { error: 'Not found' } };
+    });
+
+    const http = { get, post };
+    const client = createAngularApiClient(http as AngularHttpClientLike);
+
+    const health = await client.health();
+    expect(health.ok).toBe(true);
+    if (health.ok) {
+      expect(health.data.ok).toBe(true);
+      expect(health.data.service).toBe('partyhub');
+    }
+
+    const session = await client.getSession(' abcd12 ');
+    expect(session.ok).toBe(true);
+    if (session.ok) {
+      expect(session.data.session.code).toBe('ABCD12');
+      expect(session.data.session.host_id).toBe(1);
+      expect(session.data.phase_view_model.host.can_start_round).toBe(true);
+    }
+
+    const join = await client.joinSession({ code: ' abcd12 ', nickname: ' Maja ' });
+    expect(join.ok).toBe(true);
+
+    const start = await client.startRound(' abcd12 ', { category_slug: 'history' });
+    expect(start.ok).toBe(true);
+
+    expect(get).toHaveBeenNthCalledWith(1, '/healthz', { withCredentials: true });
+    expect(get).toHaveBeenNthCalledWith(2, '/lobby/sessions/ABCD12', { withCredentials: true });
+    expect(post).toHaveBeenNthCalledWith(
+      1,
+      '/lobby/sessions/join',
+      { code: 'ABCD12', nickname: 'Maja' },
+      { withCredentials: true }
+    );
+    expect(post).toHaveBeenNthCalledWith(
+      2,
+      '/lobby/sessions/ABCD12/rounds/start',
+      { category_slug: 'history' },
+      { withCredentials: true }
+    );
+  });
+
+  it('normalizes baseUrl with trailing slash to keep Django endpoint paths canonical', async () => {
+    const get = vi.fn<AngularHttpClientLike['get']>(async <T>(url: string) => {
+      if (url === '/api/healthz') {
+        return { ok: true, service: 'partyhub' } as T;
+      }
+      if (url === '/api/lobby/sessions/ABCD12') {
+        return {
+          session: { code: 'ABCD12', status: 'lobby', host_id: 1, current_round: 1, players_count: 2 },
+          players: [],
+          round_question: null,
+          phase_view_model: {
+            status: 'lobby',
+            round_number: 1,
+            players_count: 2,
+            constraints: {
+              min_players_to_start: 2,
+              max_players_mvp: 8,
+              min_players_reached: true,
+              max_players_allowed: true
+            },
+            host: {
+              can_start_round: true,
+              can_show_question: false,
+              can_mix_answers: false,
+              can_calculate_scores: false,
+              can_reveal_scoreboard: false,
+              can_start_next_round: false,
+              can_finish_game: false
+            },
+            player: {
+              can_join: true,
+              can_submit_lie: false,
+              can_submit_guess: false,
+              can_view_final_result: false
+            }
+          }
+        } as T;
+      }
+      throw { status: 404, error: { error: 'Not found' } };
+    });
+
+    const post = vi.fn<AngularHttpClientLike['post']>(async <T>(url: string) => {
+      if (url === '/api/lobby/sessions/join') {
+        return {
+          player: { id: 9, nickname: 'Maja', session_token: 'token-1', score: 0 },
+          session: { code: 'ABCD12', status: 'lobby' }
+        } as T;
+      }
+      if (url === '/api/lobby/sessions/ABCD12/rounds/start') {
+        return {
+          session: { code: 'ABCD12', status: 'lie', current_round: 1 },
+          round: { number: 1, category: { slug: 'history', name: 'History' } }
+        } as T;
+      }
+      throw { status: 404, error: { error: 'Not found' } };
+    });
+
+    const client = createAngularApiClient({ get, post } as AngularHttpClientLike, '/api/');
+
+    await client.health();
+    await client.getSession('abcd12');
+    await client.joinSession({ code: 'abcd12', nickname: 'Maja' });
+    await client.startRound('abcd12', { category_slug: 'history' });
+
+    expect(get).toHaveBeenNthCalledWith(1, '/api/healthz', { withCredentials: true });
+    expect(get).toHaveBeenNthCalledWith(2, '/api/lobby/sessions/ABCD12', { withCredentials: true });
+    expect(post).toHaveBeenNthCalledWith(
+      1,
+      '/api/lobby/sessions/join',
+      { code: 'ABCD12', nickname: 'Maja' },
+      { withCredentials: true }
+    );
+    expect(post).toHaveBeenNthCalledWith(
+      2,
+      '/api/lobby/sessions/ABCD12/rounds/start',
+      { category_slug: 'history' },
+      { withCredentials: true }
+    );
+  });
+
+  it('returns parse error when successful payload breaks typed contract', async () => {
+    const http = {
+      get: vi.fn<AngularHttpClientLike['get']>(async <T>() => ({ ok: true } as T)),
+      post: vi.fn<AngularHttpClientLike['post']>(async <T>() => ({ ok: true } as T))
+    };
+
+    const client = createAngularApiClient(http as AngularHttpClientLike);
+    const session = await client.getSession('ABCD12');
+
+    expect(session.ok).toBe(false);
+    if (!session.ok) {
+      expect(session.status).toBe(200);
+      expect(session.error.kind).toBe('parse');
+      expect(session.error.message).toContain('Invalid API contract');
+    }
+  });
+
+  it('keeps canonical reveal payload stable when session detail is already in scoreboard phase', async () => {
+    const get = vi.fn<AngularHttpClientLike['get']>(async <T>(url: string) => {
+      if (url === '/lobby/sessions/ABCD12') {
+        return {
+          session: { code: 'ABCD12', status: 'scoreboard', host_id: 1, current_round: 1, players_count: 2 },
+          players: [
+            { id: 2, nickname: 'Maja', score: 10, is_connected: true },
+            { id: 3, nickname: 'Bo', score: 7, is_connected: true }
+          ],
+          round_question: {
+            id: 77,
+            round_number: 1,
+            prompt: 'Q?',
+            shown_at: '2026-03-01T18:00:00Z',
+            answers: [{ text: 'A' }, { text: 'B' }]
+          },
+          reveal: {
+            round_question_id: 77,
+            round_number: 1,
+            prompt: 'Q?',
+            correct_answer: 'A',
+            lies: [{ player_id: 2, nickname: 'Maja', text: 'B', created_at: '2026-03-01T18:00:05Z' }],
+            guesses: [
+              {
+                player_id: 3,
+                nickname: 'Bo',
+                selected_text: 'B',
+                is_correct: false,
+                fooled_player_id: 2,
+                fooled_player_nickname: 'Maja',
+                created_at: '2026-03-01T18:00:15Z'
+              }
+            ]
+          },
+          phase_view_model: {
+            status: 'scoreboard',
+            round_number: 1,
+            players_count: 2,
+            constraints: {
+              min_players_to_start: 2,
+              max_players_mvp: 8,
+              min_players_reached: true,
+              max_players_allowed: true
+            },
+            host: {
+              can_start_round: false,
+              can_show_question: false,
+              can_mix_answers: false,
+              can_calculate_scores: false,
+              can_reveal_scoreboard: false,
+              can_start_next_round: true,
+              can_finish_game: true
+            },
+            player: {
+              can_join: true,
+              can_submit_lie: false,
+              can_submit_guess: false,
+              can_view_final_result: false
+            }
+          }
+        } as T;
+      }
+      throw { status: 404, error: { error: 'Not found' } };
+    });
+
+    const client = createAngularApiClient({ get, post: vi.fn() } as unknown as AngularHttpClientLike);
+    const session = await client.getSession('abcd12');
+
+    expect(session.ok).toBe(true);
+    if (session.ok) {
+      expect(session.data.session.status).toBe('scoreboard');
+      expect(session.data.reveal?.guesses[0].fooled_player_nickname).toBe('Maja');
+      expect(session.data.phase_view_model.host.can_start_next_round).toBe(true);
+      expect(session.data.phase_view_model.host.can_finish_game).toBe(true);
+    }
+  });
+
+  it('normalizes omitted fooled_player_id to null in canonical reveal payloads', async () => {
+    const get = vi.fn<AngularHttpClientLike['get']>(async <T>(url: string) => {
+      if (url === '/lobby/sessions/ABCD12') {
+        return {
+          session: { code: 'ABCD12', status: 'reveal', host_id: 1, current_round: 1, players_count: 2 },
+          players: [
+            { id: 2, nickname: 'Maja', score: 10, is_connected: true },
+            { id: 3, nickname: 'Bo', score: 7, is_connected: true }
+          ],
+          round_question: {
+            id: 77,
+            round_number: 1,
+            prompt: 'Q?',
+            shown_at: '2026-03-01T18:00:00Z',
+            answers: [{ text: 'A' }, { text: 'B' }]
+          },
+          reveal: {
+            round_question_id: 77,
+            round_number: 1,
+            prompt: 'Q?',
+            correct_answer: 'A',
+            lies: [],
+            guesses: [
+              {
+                player_id: 3,
+                nickname: 'Bo',
+                selected_text: 'A',
+                is_correct: true,
+                created_at: '2026-03-01T18:00:15Z'
+              }
+            ]
+          },
+          phase_view_model: {
+            status: 'reveal',
+            round_number: 1,
+            players_count: 2,
+            constraints: {
+              min_players_to_start: 2,
+              max_players_mvp: 8,
+              min_players_reached: true,
+              max_players_allowed: true
+            },
+            host: {
+              can_start_round: false,
+              can_show_question: false,
+              can_mix_answers: false,
+              can_calculate_scores: false,
+              can_reveal_scoreboard: true,
+              can_start_next_round: false,
+              can_finish_game: false
+            },
+            player: {
+              can_join: true,
+              can_submit_lie: false,
+              can_submit_guess: false,
+              can_view_final_result: false
+            }
+          }
+        } as T;
+      }
+      throw { status: 404, error: { error: 'Not found' } };
+    });
+
+    const post = vi.fn<AngularHttpClientLike['post']>(async <T>(url: string, body: unknown) => {
+      if (url === '/lobby/sessions/ABCD12/questions/77/guesses/submit') {
+        expect(body).toEqual({ player_id: 9, session_token: 'tok', selected_text: 'A' });
+        return {
+          guess: {
+            id: 200,
+            player_id: 9,
+            round_question_id: 77,
+            selected_text: 'A',
+            is_correct: false,
+            created_at: '2026-03-01T16:01:00Z'
+          },
+          window: { guess_deadline_at: '2026-03-01T16:01:30Z' }
+        } as T;
+      }
+      throw { status: 404, error: { error: 'Not found' } };
+    });
+
+    const client = createAngularApiClient({ get, post } as AngularHttpClientLike);
+    const session = await client.getSession('abcd12');
+
+    expect(session.ok).toBe(true);
+    if (session.ok) {
+      expect(session.data.reveal?.guesses[0].fooled_player_id).toBeNull();
+      expect(session.data.reveal?.guesses[0]).not.toHaveProperty('fooled_player_nickname');
+    }
+
+    const submitGuess = await client.submitGuess('ABCD12', 77, {
+      player_id: 9,
+      session_token: 'tok',
+      selected_text: 'A'
+    });
+    expect(submitGuess.ok).toBe(true);
+    if (submitGuess.ok) {
+      expect(submitGuess.data.guess.fooled_player_id).toBeNull();
+    }
+  });
+
+  it('maps omitted fooled_player_id to null in submit guess mapper payloads', () => {
+    const mapped = mapSubmitGuessResponse({
+      guess: {
+        id: 200,
+        player_id: 9,
+        round_question_id: 77,
+        selected_text: 'A',
+        is_correct: false,
+        created_at: '2026-03-01T16:01:00Z'
+      },
+      window: { guess_deadline_at: '2026-03-01T16:01:30Z' }
+    });
+
+    expect(mapped.guess.fooled_player_id).toBeNull();
+  });
+
+  it('keeps fooled_player_nickname omitted when canonical reveal payload omits fooled player refs', () => {
+    const mapped = mapSessionDetailResponse({
+      session: { code: 'ABCD12', status: 'reveal', host_id: 1, current_round: 1, players_count: 2 },
+      players: [
+        { id: 2, nickname: 'Maja', score: 10, is_connected: true },
+        { id: 3, nickname: 'Bo', score: 7, is_connected: true }
+      ],
+      round_question: {
+        id: 77,
+        round_number: 1,
+        prompt: 'Q?',
+        shown_at: '2026-03-01T18:00:00Z',
+        answers: [{ text: 'A' }, { text: 'B' }]
+      },
+      reveal: {
+        round_question_id: 77,
+        round_number: 1,
+        prompt: 'Q?',
+        correct_answer: 'A',
+        lies: [],
+        guesses: [
+          {
+            player_id: 3,
+            nickname: 'Bo',
+            selected_text: 'A',
+            is_correct: true,
+            created_at: '2026-03-01T18:00:15Z'
+          }
+        ]
+      },
+      phase_view_model: {
+        status: 'reveal',
+        round_number: 1,
+        players_count: 2,
+        constraints: {
+          min_players_to_start: 2,
+          max_players_mvp: 8,
+          min_players_reached: true,
+          max_players_allowed: true
+        },
+        host: {
+          can_start_round: false,
+          can_show_question: false,
+          can_mix_answers: false,
+          can_calculate_scores: false,
+          can_reveal_scoreboard: true,
+          can_start_next_round: false,
+          can_finish_game: false
+        },
+        player: {
+          can_join: true,
+          can_submit_lie: false,
+          can_submit_guess: false,
+          can_view_final_result: false
+        }
+      }
+    });
+
+    expect(mapped.reveal?.guesses[0].fooled_player_id).toBeNull();
+    expect(mapped.reveal?.guesses[0]).not.toHaveProperty('fooled_player_nickname');
+  });
+
+  it('rejects canonical reveal payloads that include fooled_player_nickname without fooled_player_id', () => {
+    expect(() =>
+      mapSessionDetailResponse({
+        session: { code: 'ABCD12', status: 'reveal', host_id: 1, current_round: 1, players_count: 2 },
+        players: [
+          { id: 2, nickname: 'Maja', score: 10, is_connected: true },
+          { id: 3, nickname: 'Bo', score: 7, is_connected: true }
+        ],
+        round_question: {
+          id: 77,
+          round_number: 1,
+          prompt: 'Q?',
+          shown_at: '2026-03-01T18:00:00Z',
+          answers: [{ text: 'A' }, { text: 'B' }]
+        },
+        reveal: {
+          round_question_id: 77,
+          round_number: 1,
+          prompt: 'Q?',
+          correct_answer: 'A',
+          lies: [],
+          guesses: [
+            {
+              player_id: 3,
+              nickname: 'Bo',
+              selected_text: 'A',
+              is_correct: true,
+              fooled_player_nickname: 'Maja',
+              created_at: '2026-03-01T18:00:15Z'
+            }
+          ]
+        },
+        phase_view_model: {
+          status: 'reveal',
+          round_number: 1,
+          players_count: 2,
+          constraints: {
+            min_players_to_start: 2,
+            max_players_mvp: 8,
+            min_players_reached: true,
+            max_players_allowed: true
+          },
+          host: {
+            can_start_round: false,
+            can_show_question: false,
+            can_mix_answers: false,
+            can_calculate_scores: false,
+            can_reveal_scoreboard: true,
+            can_start_next_round: false,
+            can_finish_game: false
+          },
+          player: {
+            can_join: true,
+            can_submit_lie: false,
+            can_submit_guess: false,
+            can_view_final_result: false
+          }
+        }
+      })
+    ).toThrow('fooled_player_nickname to be omitted when fooled_player_id is null');
+  });
+
+  it('rejects canonical reveal payloads that omit fooled_player_nickname when fooled_player_id is set', () => {
+    expect(() =>
+      mapSessionDetailResponse({
+        session: { code: 'ABCD12', status: 'reveal', host_id: 1, current_round: 1, players_count: 2 },
+        players: [
+          { id: 2, nickname: 'Maja', score: 10, is_connected: true },
+          { id: 3, nickname: 'Bo', score: 7, is_connected: true }
+        ],
+        round_question: {
+          id: 77,
+          round_number: 1,
+          prompt: 'Q?',
+          shown_at: '2026-03-01T18:00:00Z',
+          answers: [{ text: 'A' }, { text: 'B' }]
+        },
+        reveal: {
+          round_question_id: 77,
+          round_number: 1,
+          prompt: 'Q?',
+          correct_answer: 'A',
+          lies: [],
+          guesses: [
+            {
+              player_id: 3,
+              nickname: 'Bo',
+              selected_text: 'B',
+              is_correct: false,
+              fooled_player_id: 2,
+              created_at: '2026-03-01T18:00:15Z'
+            }
+          ]
+        },
+        phase_view_model: {
+          status: 'reveal',
+          round_number: 1,
+          players_count: 2,
+          constraints: {
+            min_players_to_start: 2,
+            max_players_mvp: 8,
+            min_players_reached: true,
+            max_players_allowed: true
+          },
+          host: {
+            can_start_round: false,
+            can_show_question: false,
+            can_mix_answers: false,
+            can_calculate_scores: false,
+            can_reveal_scoreboard: true,
+            can_start_next_round: false,
+            can_finish_game: false
+          },
+          player: {
+            can_join: true,
+            can_submit_lie: false,
+            can_submit_guess: false,
+            can_view_final_result: false
+          }
+        }
+      })
+    ).toThrow('fooled_player_nickname when fooled_player_id is set');
+  });
+
+  it('maps host/player gameplay endpoints through typed response mappers', async () => {
+    const get = vi.fn<AngularHttpClientLike['get']>(async <T>(url: string) => {
+      if (url === '/lobby/sessions/ABCD12/scoreboard') {
+        return {
+          session: { code: 'ABCD12', status: 'scoreboard', current_round: 1 },
+          leaderboard: [
+            { id: 2, nickname: 'Maja', score: 11 },
+            { id: 3, nickname: 'Bo', score: 7 }
+          ]
+        } as T;
+      }
+      throw { status: 404, error: { error: 'Not found' } };
+    });
+
+    const post = vi.fn<AngularHttpClientLike['post']>(async <T>(url: string, body: unknown) => {
+      if (url === '/lobby/sessions/ABCD12/questions/show') {
+        expect(body).toEqual({});
+        return {
+          round_question: {
+            id: 77,
+            prompt: 'Prompt?',
+            round_number: 1,
+            shown_at: '2026-03-01T16:00:00Z',
+            lie_deadline_at: '2026-03-01T16:00:30Z'
+          },
+          config: { lie_seconds: 30 }
+        } as T;
+      }
+      if (url === '/lobby/sessions/ABCD12/questions/77/answers/mix') {
+        expect(body).toEqual({});
+        return {
+          session: { code: 'ABCD12', status: 'guess', current_round: 1 },
+          round_question: { id: 77, round_number: 1 },
+          answers: [{ text: 'A' }, { text: 'B' }]
+        } as T;
+      }
+      if (url === '/lobby/sessions/ABCD12/questions/77/scores/calculate') {
+        expect(body).toEqual({});
+        return {
+          session: { code: 'ABCD12', status: 'scoreboard', current_round: 1 },
+          round_question: { id: 77, round_number: 1 },
+          events_created: 3,
+          leaderboard: [{ id: 2, nickname: 'Maja', score: 11 }]
+        } as T;
+      }
+      if (url === '/lobby/sessions/ABCD12/rounds/next') {
+        expect(body).toEqual({});
+        return { session: { code: 'ABCD12', status: 'lie', current_round: 2 } } as T;
+      }
+      if (url === '/lobby/sessions/ABCD12/finish') {
+        expect(body).toEqual({});
+        return {
+          session: { code: 'ABCD12', status: 'finished', current_round: 2 },
+          winner: { id: 2, nickname: 'Maja', score: 15 },
+          leaderboard: [{ id: 2, nickname: 'Maja', score: 15 }]
+        } as T;
+      }
+      if (url === '/lobby/sessions/ABCD12/questions/77/lies/submit') {
+        expect(body).toEqual({ player_id: 9, session_token: 'tok', text: 'my lie' });
+        return {
+          lie: {
+            id: 100,
+            player_id: 9,
+            round_question_id: 77,
+            text: 'my lie',
+            created_at: '2026-03-01T16:00:10Z'
+          },
+          window: { lie_deadline_at: '2026-03-01T16:00:30Z' }
+        } as T;
+      }
+      if (url === '/lobby/sessions/ABCD12/questions/77/guesses/submit') {
+        expect(body).toEqual({ player_id: 9, session_token: 'tok', selected_text: 'A' });
+        return {
+          guess: {
+            id: 200,
+            player_id: 9,
+            round_question_id: 77,
+            selected_text: 'A',
+            is_correct: false,
+            fooled_player_id: 3,
+            created_at: '2026-03-01T16:01:00Z'
+          },
+          window: { guess_deadline_at: '2026-03-01T16:01:30Z' }
+        } as T;
+      }
+
+      throw { status: 404, error: { error: 'Not found' } };
+    });
+
+    const client = createAngularApiClient({ get, post } as AngularHttpClientLike);
+
+    const showQuestion = await client.showQuestion('abcd12');
+    expect(showQuestion.ok).toBe(true);
+
+    const mixAnswers = await client.mixAnswers('abcd12', 77);
+    expect(mixAnswers.ok).toBe(true);
+
+    const calculateScores = await client.calculateScores('abcd12', 77);
+    expect(calculateScores.ok).toBe(true);
+
+    const scoreboard = await client.getScoreboard('abcd12');
+    expect(scoreboard.ok).toBe(true);
+
+    const nextRound = await client.startNextRound('abcd12');
+    expect(nextRound.ok).toBe(true);
+
+    const finish = await client.finishGame('abcd12');
+    expect(finish.ok).toBe(true);
+
+    const submitLie = await client.submitLie('abcd12', 77, { player_id: 9, session_token: 'tok', text: 'my lie' });
+    expect(submitLie.ok).toBe(true);
+
+    const submitGuess = await client.submitGuess('abcd12', 77, {
+      player_id: 9,
+      session_token: 'tok',
+      selected_text: 'A'
+    });
+    expect(submitGuess.ok).toBe(true);
+  });
+
+  it('maps HttpErrorResponse-style failures to ApiResult errors', async () => {
+    const http = {
+      get: vi.fn<AngularHttpClientLike['get']>(async () => {
+        throw { status: 503, message: 'Service unavailable', error: { error: 'maintenance' } };
+      }),
+      post: vi.fn<AngularHttpClientLike['post']>(async () => {
+        throw { status: 403, message: 'Forbidden', error: { error: 'Only host can start round' } };
+      })
+    };
+
+    const client = createAngularApiClient(http as AngularHttpClientLike);
+    const health = await client.health();
+
+    expect(health.ok).toBe(false);
+    if (!health.ok) {
+      expect(health.status).toBe(503);
+      expect(health.error.kind).toBe('http');
+      expect(health.error.payload).toEqual({ error: 'maintenance' });
+      expect(health.error.message).toContain('Service unavailable');
+    }
+
+    const start = await client.startRound('ABCD12', { category_slug: 'history' });
+    expect(start.ok).toBe(false);
+    if (!start.ok) {
+      expect(start.status).toBe(403);
+      expect(start.error.kind).toBe('http');
+      expect(start.error.payload).toEqual({ error: 'Only host can start round' });
+    }
+  });
+});

frontend/tests/api-client.integration.test.ts

@@ -0,0 +1,166 @@
+import { afterAll, beforeAll, describe, expect, it } from 'vitest';
+import { AddressInfo } from 'node:net';
+import { createServer, type IncomingMessage, type Server, type ServerResponse } from 'node:http';
+import { createApiClient } from '../src/api/client';
+
+let server: Server;
+let baseUrl: string;
+
+beforeAll(async () => {
+  server = createServer(async (req: IncomingMessage, res: ServerResponse) => {
+    if (req.url === '/healthz') {
+      res.writeHead(200, { 'content-type': 'application/json' });
+      res.end(JSON.stringify({ ok: true, service: 'weirsoe-party-protocol' }));
+      return;
+    }
+
+    if (req.url === '/lobby/sessions/ABCD12' && req.method === 'GET') {
+      res.writeHead(200, { 'content-type': 'application/json' });
+      res.end(
+        JSON.stringify({
+          session: { code: 'ABCD12', status: 'lobby', host_id: 1, current_round: 1, players_count: 3 },
+          players: [],
+          round_question: null,
+          phase_view_model: {
+            status: 'lobby',
+            round_number: 1,
+            players_count: 3,
+            constraints: {
+              min_players_to_start: 3,
+              max_players_mvp: 5,
+              min_players_reached: true,
+              max_players_allowed: true
+            },
+            host: {
+              can_start_round: true,
+              can_show_question: false,
+              can_mix_answers: false,
+              can_calculate_scores: false,
+              can_reveal_scoreboard: false,
+              can_start_next_round: false,
+              can_finish_game: false
+            },
+            player: {
+              can_join: true,
+              can_submit_lie: false,
+              can_submit_guess: false,
+              can_view_final_result: false
+            }
+          }
+        })
+      );
+      return;
+    }
+
+    if (req.url === '/lobby/sessions/join' && req.method === 'POST') {
+      res.writeHead(201, { 'content-type': 'application/json' });
+      res.end(
+        JSON.stringify({
+          player: { id: 9, nickname: 'Maja', session_token: 'token-1', score: 0 },
+          session: { code: 'ABCD12', status: 'lobby' }
+        })
+      );
+      return;
+    }
+
+    if (req.url === '/lobby/sessions/ABCD12/rounds/start' && req.method === 'POST') {
+      res.writeHead(201, { 'content-type': 'application/json' });
+      res.end(
+        JSON.stringify({
+          session: { code: 'ABCD12', status: 'lie', current_round: 1 },
+          round: { number: 1, category: { slug: 'history', name: 'History' } }
+        })
+      );
+      return;
+    }
+
+    if (req.url === '/lobby/sessions/BADMAP' && req.method === 'GET') {
+      res.writeHead(200, { 'content-type': 'application/json' });
+      res.end(JSON.stringify({ session: { code: 'BADMAP' } }));
+      return;
+    }
+
+    if (req.url?.startsWith('/lobby/sessions/')) {
+      res.writeHead(404, { 'content-type': 'application/json' });
+      res.end(JSON.stringify({ error: 'Session not found' }));
+      return;
+    }
+
+    res.writeHead(500, { 'content-type': 'application/json' });
+    res.end(JSON.stringify({ error: 'unexpected route' }));
+  });
+
+  await new Promise<void>((resolve) => server.listen(0, '127.0.0.1', () => resolve()));
+  const { port } = server.address() as AddressInfo;
+  baseUrl = `http://127.0.0.1:${port}`;
+});
+
+afterAll(async () => {
+  await new Promise<void>((resolve, reject) =>
+    server.close((err?: Error) => (err ? reject(err) : resolve()))
+  );
+});
+
+describe('createApiClient', () => {
+  it('reads health + session detail through typed wrappers', async () => {
+    const client = createApiClient(baseUrl);
+
+    const health = await client.health();
+    expect(health.ok).toBe(true);
+
+    const session = await client.getSession('abcd12');
+    expect(session.ok).toBe(true);
+    if (session.ok) {
+      expect(session.data.session.code).toBe('ABCD12');
+      expect(session.data.phase_view_model.host.can_start_round).toBe(true);
+    }
+  });
+
+  it('supports join + start round writes for lobby vertical slice', async () => {
+    const client = createApiClient(baseUrl);
+
+    const join = await client.joinSession({ code: 'abcd12', nickname: 'Maja' });
+    expect(join.ok).toBe(true);
+
+    const start = await client.startRound('abcd12', { category_slug: 'history' });
+    expect(start.ok).toBe(true);
+    if (start.ok) {
+      expect(start.data.session.status).toBe('lie');
+    }
+  });
+
+  it('returns parse error when response violates typed contract', async () => {
+    const client = createApiClient(baseUrl);
+
+    const invalid = await client.getSession('badmap');
+    expect(invalid.ok).toBe(false);
+    if (!invalid.ok) {
+      expect(invalid.status).toBe(200);
+      expect(invalid.error.kind).toBe('parse');
+      expect(invalid.error.message).toContain('Invalid API contract');
+    }
+  });
+
+  it('returns consistent HTTP error shape for 4xx/5xx', async () => {
+    const client = createApiClient(baseUrl);
+
+    const missing = await client.getSession('missing');
+    expect(missing.ok).toBe(false);
+    if (!missing.ok) {
+      expect(missing.status).toBe(404);
+      expect(missing.error.kind).toBe('http');
+      expect(missing.error.payload).toEqual({ error: 'Session not found' });
+    }
+  });
+
+  it('returns consistent network error shape', async () => {
+    const client = createApiClient('http://127.0.0.1:9');
+
+    const health = await client.health();
+    expect(health.ok).toBe(false);
+    if (!health.ok) {
+      expect(health.error.kind).toBe('network');
+      expect(health.status).toBe(0);
+    }
+  });
+});

frontend/tests/gameplay-phase-machine.test.ts

@@ -0,0 +1,150 @@
+import { describe, expect, it } from 'vitest';
+import {
+  allowedGameplayEvents,
+  deriveGameplayPhase,
+  isHostGameplayActionAllowed,
+  isPlayerGameplayActionAllowed,
+  transitionGameplayPhase,
+  type GameplayPhase
+} from '../src/spa/gameplay-phase-machine';
+
+describe('gameplay phase machine skeleton', () => {
+  it('supports canonical phase progression lie -> guess -> reveal -> scoreboard -> lie', () => {
+    let phase: GameplayPhase = 'lie';
+
+    phase = transitionGameplayPhase(phase, 'LIES_LOCKED').phase;
+    expect(phase).toBe('guess');
+
+    phase = transitionGameplayPhase(phase, 'GUESSES_LOCKED').phase;
+    expect(phase).toBe('reveal');
+
+    phase = transitionGameplayPhase(phase, 'SCOREBOARD_READY').phase;
+    expect(phase).toBe('scoreboard');
+
+    phase = transitionGameplayPhase(phase, 'NEXT_ROUND').phase;
+    expect(phase).toBe('lie');
+  });
+
+  it('keeps state unchanged for invalid transition events', () => {
+    const transition = transitionGameplayPhase('lie', 'NEXT_ROUND');
+    expect(transition.phase).toBe('lie');
+    expect(transition.changed).toBe(false);
+  });
+
+  it('exposes allowed events per phase', () => {
+    expect(allowedGameplayEvents('guess')).toEqual(['GUESSES_LOCKED']);
+    expect(allowedGameplayEvents('scoreboard')).toEqual(['NEXT_ROUND']);
+  });
+
+  it('derives gameplay phase from session detail status', () => {
+    expect(
+      deriveGameplayPhase({
+        session: { code: 'ABCD12', status: 'lie', host_id: 1, current_round: 1, players_count: 3 },
+        players: [],
+        round_question: null,
+        reveal: null,
+        phase_view_model: {
+          status: 'lie',
+          round_number: 1,
+          players_count: 3,
+          constraints: {
+            min_players_to_start: 3,
+            max_players_mvp: 5,
+            min_players_reached: true,
+            max_players_allowed: true
+          },
+          host: {
+            can_start_round: false,
+            can_show_question: true,
+            can_mix_answers: true,
+            can_calculate_scores: false,
+            can_reveal_scoreboard: false,
+            can_start_next_round: false,
+            can_finish_game: false
+          },
+          player: {
+            can_join: false,
+            can_submit_lie: true,
+            can_submit_guess: false,
+            can_view_final_result: false
+          }
+        }
+      })
+    ).toBe('lie');
+
+    expect(
+      deriveGameplayPhase({
+        session: { code: 'ABCD12', status: 'finished', host_id: 1, current_round: 1, players_count: 3 },
+        players: [],
+        round_question: null,
+        reveal: null,
+        phase_view_model: {
+          status: 'finished',
+          round_number: 1,
+          players_count: 3,
+          constraints: {
+            min_players_to_start: 3,
+            max_players_mvp: 5,
+            min_players_reached: true,
+            max_players_allowed: true
+          },
+          host: {
+            can_start_round: false,
+            can_show_question: false,
+            can_mix_answers: false,
+            can_calculate_scores: false,
+            can_reveal_scoreboard: false,
+            can_start_next_round: false,
+            can_finish_game: false
+          },
+          player: {
+            can_join: false,
+            can_submit_lie: false,
+            can_submit_guess: false,
+            can_view_final_result: true
+          }
+        }
+      })
+    ).toBe('scoreboard');
+  });
+
+  it('gates host and player actions from canonical phase_view_model permissions', () => {
+    const session = {
+      session: { code: 'ABCD12', status: 'scoreboard', host_id: 1, current_round: 1, players_count: 3 },
+      players: [],
+      round_question: { id: 77, prompt: 'Q?', answers: [] },
+      phase_view_model: {
+        status: 'reveal',
+        round_number: 1,
+        players_count: 3,
+        constraints: {
+          min_players_to_start: 3,
+          max_players_mvp: 5,
+          min_players_reached: true,
+          max_players_allowed: true
+        },
+        host: {
+          can_start_round: false,
+          can_show_question: false,
+          can_mix_answers: false,
+          can_calculate_scores: false,
+          can_reveal_scoreboard: true,
+          can_start_next_round: true,
+          can_finish_game: true
+        },
+        player: {
+          can_join: false,
+          can_submit_lie: false,
+          can_submit_guess: false,
+          can_view_final_result: false
+        }
+      }
+    } as const;
+
+    expect(deriveGameplayPhase(session as any)).toBe('reveal');
+    expect(isHostGameplayActionAllowed(session as any, 'loadScoreboard')).toBe(true);
+    expect(isHostGameplayActionAllowed(session as any, 'startNextRound')).toBe(true);
+    expect(isHostGameplayActionAllowed(session as any, 'finishGame')).toBe(true);
+    expect(isPlayerGameplayActionAllowed(session as any, 'submitGuess')).toBe(false);
+  });
+});

frontend/tests/lobby-i18n.contract.test.ts

@@ -0,0 +1,68 @@
+import { describe, expect, it } from 'vitest';
+
+import lobbyCatalog from '../../shared/i18n/lobby.json';
+import { lobbyMessage, lobbyMessageFromApiPayload } from '../src/spa/lobby-i18n';
+
+describe('shared i18n keyspace contract', () => {
+  it('keeps en as default and da/en matrix for frontend error keys', () => {
+    expect(lobbyCatalog.locales.default).toBe('en');
+    expect(lobbyCatalog.locales.supported).toEqual(expect.arrayContaining(['en', 'da']));
+
+    for (const [key, translations] of Object.entries(lobbyCatalog.frontend.errors)) {
+      expect(translations.en, `${key} missing en`).toBeTruthy();
+      expect(translations.da, `${key} missing da`).toBeTruthy();
+    }
+  });
+
+  it('keeps backend error-code keyspace aligned with shared backend→frontend map and backend translations', () => {
+    for (const [code, backendKey] of Object.entries(lobbyCatalog.backend.error_codes)) {
+      const frontendKey =
+        lobbyCatalog.contract.backend_to_frontend_error_keys[
+          code as keyof typeof lobbyCatalog.contract.backend_to_frontend_error_keys
+        ];
+
+      expect(lobbyCatalog.backend.errors[backendKey as keyof typeof lobbyCatalog.backend.errors]).toBeDefined();
+      expect(frontendKey, `missing frontend mapping for ${code}`).toBeTruthy();
+      expect(lobbyCatalog.frontend.errors[frontendKey as keyof typeof lobbyCatalog.frontend.errors]).toBeDefined();
+    }
+
+    for (const [key, translations] of Object.entries(lobbyCatalog.backend.errors)) {
+      expect(translations.en, `${key} missing en`).toBeTruthy();
+      expect(translations.da, `${key} missing da`).toBeTruthy();
+    }
+  });
+});
+
+describe('lobbyMessage locale handling', () => {
+  it('uses english by default and falls back to default for unsupported locale', () => {
+    expect(lobbyMessage('session_code_required')).toBe('Session code is required.');
+    expect(lobbyMessage('session_code_required', 'fr')).toBe('Session code is required.');
+  });
+
+  it('resolves locale from api payload and maps known backend error codes directly', () => {
+    expect(
+      lobbyMessageFromApiPayload(
+        { error_code: 'session_not_found', locale: 'da' },
+        'join_failed',
+      ),
+    ).toBe('Sessionskoden er ugyldig, eller sessionen findes ikke længere.');
+  });
+
+  it('uses shared backend→frontend key-map at runtime even when fallback key differs', () => {
+    expect(
+      lobbyMessageFromApiPayload(
+        { error_code: 'session_not_joinable', locale: 'da' },
+        'start_round_failed',
+      ),
+    ).toBe('Kunne ikke joine. Tjek kode eller kaldenavn og prøv igen.');
+  });
+
+  it('falls back to caller-provided fallback key for unknown backend error codes', () => {
+    expect(
+      lobbyMessageFromApiPayload(
+        { error_code: 'unknown_backend_key', locale: 'da' },
+        'join_failed',
+      ),
+    ).toBe('Kunne ikke joine. Tjek kode eller kaldenavn og prøv igen.');
+  });
+});

frontend/tests/lobby-loader.parity.test.ts

@@ -0,0 +1,38 @@
+import { describe, expect, it } from 'vitest';
+
+import {
+  collectLocaleParityIssues,
+  LOBBY_I18N_CATALOG,
+  normalizeLocale,
+  SUPPORTED_LOCALES,
+  translateCatalogPath,
+} from '../shared/i18n/lobby-loader';
+
+describe('shared lobby i18n loader parity', () => {
+  it('keeps da/en translation parity in shared keyspace', () => {
+    const issues = collectLocaleParityIssues(LOBBY_I18N_CATALOG, SUPPORTED_LOCALES);
+    expect(issues).toEqual([]);
+  });
+
+  it('normalizes browser-style locale tags to supported keyspace locales', () => {
+    expect(normalizeLocale('da-DK')).toBe('da');
+    expect(normalizeLocale('da_DK')).toBe('da');
+    expect(normalizeLocale('en-US')).toBe('en');
+    expect(normalizeLocale('en_US')).toBe('en');
+    expect(normalizeLocale('fr-FR')).toBe('en');
+  });
+
+  it('resolves shared frontend ui keys with fallback-safe behavior', () => {
+    expect(
+      translateCatalogPath(LOBBY_I18N_CATALOG.frontend.ui as Record<string, unknown>, 'host.start_round', 'da-DK'),
+    ).toBe('Start runde');
+
+    expect(
+      translateCatalogPath(LOBBY_I18N_CATALOG.frontend.ui as Record<string, unknown>, 'app.language_label', 'en-US'),
+    ).toBe('Language');
+
+    expect(
+      translateCatalogPath(LOBBY_I18N_CATALOG.frontend.ui as Record<string, unknown>, 'host.non_existing_key', 'da'),
+    ).toBe('host.non_existing_key');
+  });
+});

frontend/tests/session-context-store.test.ts

@@ -0,0 +1,56 @@
+import { describe, expect, it } from 'vitest';
+import { createSessionContextStore, type StorageLike } from '../src/spa/session-context-store';
+
+function makeMemoryStorage(seed?: Record<string, string>): StorageLike {
+  const memory = new Map<string, string>(Object.entries(seed ?? {}));
+  return {
+    getItem: (key: string) => memory.get(key) ?? null,
+    setItem: (key: string, value: string) => {
+      memory.set(key, value);
+    },
+    removeItem: (key: string) => {
+      memory.delete(key);
+    }
+  };
+}
+
+describe('session context store', () => {
+  it('normalizes and persists sessionCode/playerId/token', () => {
+    const storage = makeMemoryStorage();
+    const store = createSessionContextStore(storage, 'ctx');
+
+    const value = store.set({ sessionCode: ' abcd12 ', playerId: 12, token: ' token-1 ' });
+    expect(value).toEqual({ sessionCode: 'ABCD12', playerId: 12, token: 'token-1' });
+
+    expect(store.get()).toEqual({ sessionCode: 'ABCD12', playerId: 12, token: 'token-1' });
+    expect(storage.getItem('ctx')).toBe('{"sessionCode":"ABCD12","playerId":12,"token":"token-1"}');
+  });
+
+  it('loads from storage and clears invalid payloads', () => {
+    const storage = makeMemoryStorage({ ctx: '{"sessionCode":"","playerId":0,"token":""}' });
+    const store = createSessionContextStore(storage, 'ctx');
+
+    expect(store.get()).toBeNull();
+    expect(storage.getItem('ctx')).toBeNull();
+  });
+
+  it('supports clear()', () => {
+    const storage = makeMemoryStorage();
+    const store = createSessionContextStore(storage, 'ctx');
+
+    store.set({ sessionCode: 'ABCD12', playerId: 3, token: 'token-3' });
+    store.clear();
+
+    expect(store.get()).toBeNull();
+    expect(storage.getItem('ctx')).toBeNull();
+  });
+
+  it('rejects invalid context writes', () => {
+    const store = createSessionContextStore();
+    expect(() => store.set({ sessionCode: '', playerId: 1, token: 'token-1' })).toThrow('sessionCode is required');
+    expect(() => store.set({ sessionCode: 'ABCD12', playerId: 0, token: 'token-1' })).toThrow(
+      'playerId must be a positive integer'
+    );
+    expect(() => store.set({ sessionCode: 'ABCD12', playerId: 2, token: '   ' })).toThrow('token is required');
+  });
+});

frontend/tests/vertical-slice.test.ts

@@ -0,0 +1,236 @@
+import { describe, expect, it, vi } from 'vitest';
+import {
+  createVerticalSliceController,
+  type SessionContext,
+  type SessionContextStore
+} from '../src/spa/vertical-slice';
+import type { ApiClient } from '../src/api/client';
+
+function makeApiMock(overrides?: Partial<ApiClient>): ApiClient {
+  const base: ApiClient = {
+    health: vi.fn(),
+    getSession: vi.fn().mockResolvedValue({
+      ok: true,
+      status: 200,
+      data: {
+        session: { code: 'ABCD12', status: 'lobby', host_id: 1, current_round: 1, players_count: 3 },
+        players: [],
+        round_question: null,
+        reveal: null,
+        phase_view_model: {
+          status: 'lobby',
+          round_number: 1,
+          players_count: 3,
+          constraints: {
+            min_players_to_start: 3,
+            max_players_mvp: 5,
+            min_players_reached: true,
+            max_players_allowed: true
+          },
+          host: {
+            can_start_round: true,
+            can_show_question: false,
+            can_mix_answers: false,
+            can_calculate_scores: false,
+            can_reveal_scoreboard: false,
+            can_start_next_round: false,
+            can_finish_game: false
+          },
+          player: {
+            can_join: true,
+            can_submit_lie: false,
+            can_submit_guess: false,
+            can_view_final_result: false
+          }
+        }
+      }
+    }),
+    joinSession: vi.fn().mockResolvedValue({
+      ok: true,
+      status: 201,
+      data: { player: { id: 9, nickname: 'Maja', session_token: 'token-1', score: 0 }, session: { code: 'ABCD12', status: 'lobby' } }
+    }),
+    startRound: vi.fn().mockResolvedValue({
+      ok: true,
+      status: 201,
+      data: {
+        session: { code: 'ABCD12', status: 'lie', current_round: 1 },
+        round: { number: 1, category: { slug: 'history', name: 'History' } }
+      }
+    }),
+    showQuestion: vi.fn(),
+    mixAnswers: vi.fn(),
+    calculateScores: vi.fn(),
+    getScoreboard: vi.fn(),
+    startNextRound: vi.fn(),
+    finishGame: vi.fn(),
+    submitLie: vi.fn(),
+    submitGuess: vi.fn()
+  };
+
+  return { ...base, ...overrides };
+}
+
+function makeSessionContextStore(initial: SessionContext | null = null): SessionContextStore {
+  let value = initial;
+  return {
+    get: vi.fn(() => value),
+    set: vi.fn((next: SessionContext) => {
+      value = next;
+      return next;
+    })
+  };
+}
+
+describe('vertical slice controller: lobby -> join -> start round', () => {
+  it('uses createSessionContextStore by default (no manual injection)', async () => {
+    vi.resetModules();
+    const defaultStore = {
+      get: vi.fn(() => null),
+      set: vi.fn((next: SessionContext) => next),
+      clear: vi.fn()
+    };
+
+    vi.doMock('../src/spa/session-context-store', async () => {
+      const actual = await vi.importActual<typeof import('../src/spa/session-context-store')>('../src/spa/session-context-store');
+      return {
+        ...actual,
+        createSessionContextStore: vi.fn(() => defaultStore)
+      };
+    });
+
+    const { createVerticalSliceController: createControllerWithMock } = await import('../src/spa/vertical-slice');
+    const api = makeApiMock();
+    const controller = createControllerWithMock(api);
+
+    await controller.joinLobby('ABCD12', 'Maja');
+
+    expect(defaultStore.set).toHaveBeenCalledWith({
+      sessionCode: 'ABCD12',
+      playerId: 9,
+      token: 'token-1'
+    });
+
+    vi.doUnmock('../src/spa/session-context-store');
+    vi.resetModules();
+  });
+
+  it('tracks loading and success state for join + start flow', async () => {
+    const api = makeApiMock();
+    const controller = createVerticalSliceController(api);
+
+    const beforeJoinPromise = controller.joinLobby('abcd12', 'Maja');
+    expect(controller.getState().joinState).toBe('loading');
+    await beforeJoinPromise;
+
+    const postJoin = controller.getState();
+    expect(postJoin.joinState).toBe('success');
+    expect(postJoin.session?.session.code).toBe('ABCD12');
+
+    const beforeStartPromise = controller.startRound('abcd12', 'history');
+    expect(controller.getState().startRoundState).toBe('loading');
+    await beforeStartPromise;
+
+    const postStart = controller.getState();
+    expect(postStart.startRoundState).toBe('success');
+  });
+
+  it('persists session context after join and syncs normalized session code', async () => {
+    const api = makeApiMock();
+    const sessionContextStore = makeSessionContextStore();
+    const controller = createVerticalSliceController(api, sessionContextStore);
+
+    await controller.joinLobby('abcd12', 'Maja');
+
+    expect(sessionContextStore.set).toHaveBeenCalledWith({
+      sessionCode: 'ABCD12',
+      playerId: 9,
+      token: 'token-1'
+    });
+    expect(controller.getState().sessionCode).toBe('ABCD12');
+  });
+
+  it('uses stored session code as fallback for join + hydrate flow when input code is empty', async () => {
+    const api = makeApiMock();
+    const sessionContextStore = makeSessionContextStore({
+      sessionCode: 'wxyz99',
+      playerId: 5,
+      token: 'token-old'
+    });
+    const controller = createVerticalSliceController(api, sessionContextStore);
+
+    await controller.joinLobby('  ', 'Maja');
+
+    expect(api.joinSession).toHaveBeenCalledWith({ code: 'WXYZ99', nickname: 'Maja' });
+    expect(api.getSession).toHaveBeenCalledWith('ABCD12');
+  });
+
+  it('surfaces a friendly error when join fails', async () => {
+    const api = makeApiMock({
+      joinSession: vi.fn().mockResolvedValue({
+        ok: false,
+        status: 404,
+        error: { kind: 'http', status: 404, message: 'HTTP 404', payload: { error: 'Session not found', error_code: 'session_not_found' } }
+      })
+    });
+
+    const controller = createVerticalSliceController(api);
+    await controller.joinLobby('missing', 'Maja');
+
+    const state = controller.getState();
+    expect(state.joinState).toBe('error');
+    expect(state.errorMessage).toBe('Session code is invalid or the session no longer exists.');
+  });
+
+  it('surfaces a friendly error when round start fails', async () => {
+    const api = makeApiMock({
+      startRound: vi.fn().mockResolvedValue({
+        ok: false,
+        status: 400,
+        error: { kind: 'http', status: 400, message: 'HTTP 400', payload: { error: 'Round can only be started from lobby', error_code: 'round_start_invalid_phase' } }
+      })
+    });
+
+    const controller = createVerticalSliceController(api);
+    await controller.startRound('ABCD12', 'history');
+
+    const state = controller.getState();
+    expect(state.startRoundState).toBe('error');
+    expect(state.errorMessage).toBe('Could not start round. Refresh the lobby and try again.');
+  });
+
+  it('shows local validation error and avoids API call when hydrating without any session code', async () => {
+    const api = makeApiMock();
+    const controller = createVerticalSliceController(api, makeSessionContextStore(null));
+
+    await controller.hydrateLobby('   ');
+
+    const state = controller.getState();
+    expect(state.errorMessage).toBe('Session code is required.');
+    expect(state.loadingSession).toBe(false);
+    expect(api.getSession).not.toHaveBeenCalled();
+  });
+
+  it('shows local validation error and avoids API call when starting round without any session code', async () => {
+    const api = makeApiMock();
+    const controller = createVerticalSliceController(api, makeSessionContextStore(null));
+
+    await controller.startRound('   ', 'history');
+
+    const state = controller.getState();
+    expect(state.startRoundState).toBe('error');
+    expect(state.errorMessage).toBe('Session code is required.');
+    expect(api.startRound).not.toHaveBeenCalled();
+  });
+
+  it('uses joined session code when starting round without a reload', async () => {
+    const api = makeApiMock();
+    const controller = createVerticalSliceController(api);
+
+    await controller.joinLobby(' abcd12 ', 'Maja');
+    await controller.startRound('', 'history');
+
+    expect(api.startRound).toHaveBeenCalledWith('ABCD12', { category_slug: 'history' });
+    expect(controller.getState().sessionCode).toBe('ABCD12');
+  });
+});

frontend/tsconfig.json

@@ -0,0 +1,13 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "ES2022",
+    "moduleResolution": "bundler",
+    "resolveJsonModule": true,
+    "strict": true,
+    "skipLibCheck": true,
+    "lib": ["ES2022", "DOM"],
+    "types": ["vitest/globals", "node"]
+  },
+  "include": ["src", "tests", "../shared/i18n/*.json"]
+}

frontend/vitest.config.ts

@@ -0,0 +1,9 @@
+import { defineConfig } from 'vitest/config';
+
+export default defineConfig({
+  test: {
+    include: ['tests/**/*.test.ts', 'angular/src/**/*.spec.ts'],
+    setupFiles: ['angular/src/test-setup.ts'],
+    exclude: ['**/node_modules/**']
+  }
+});

fupogfakta/migrations/0005_alter_gamesession_status.py

@@ -0,0 +1,18 @@
+# Generated by Django 6.0.2 on 2026-03-13 16:05
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('fupogfakta', '0004_player_session_token'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='gamesession',
+            name='status',
+            field=models.CharField(choices=[('lobby', 'Lobby'), ('lie', 'Løgnfase'), ('guess', 'Gættefase'), ('reveal', 'Reveal'), ('scoreboard', 'Scoreboard'), ('finished', 'Afsluttet')], default='lobby', max_length=16),
+        ),
+    ]

fupogfakta/migrations/0005_gamesession_scoreboard_status.py

@@ -0,0 +1,26 @@
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("fupogfakta", "0004_player_session_token"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="gamesession",
+            name="status",
+            field=models.CharField(
+                choices=[
+                    ("lobby", "Lobby"),
+                    ("lie", "Løgnfase"),
+                    ("guess", "Gættefase"),
+                    ("reveal", "Reveal"),
+                    ("scoreboard", "Scoreboard"),
+                    ("finished", "Afsluttet"),
+                ],
+                default="lobby",
+                max_length=16,
+            ),
+        ),
+    ]

fupogfakta/migrations/0006_merge_20260315_1249.py

@@ -0,0 +1,10 @@
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("fupogfakta", "0005_alter_gamesession_status"),
+        ("fupogfakta", "0005_gamesession_scoreboard_status"),
+    ]
+
+    operations = []

fupogfakta/migrations/0007_roundconfig_started_from_scoreboard.py

@@ -0,0 +1,18 @@
+# Generated by Django 6.0.2 on 2026-03-17 08:24
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('fupogfakta', '0006_merge_20260315_1249'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='roundconfig',
+            name='started_from_scoreboard',
+            field=models.BooleanField(default=False),
+        ),
+    ]

fupogfakta/models.py

@@ -42,6 +42,7 @@ class GameSession(models.Model):
         LIE = "lie", "Løgnfase"
         GUESS = "guess", "Gættefase"
         REVEAL = "reveal", "Reveal"
+        SCOREBOARD = "scoreboard", "Scoreboard"
         FINISHED = "finished", "Afsluttet"
 
     host = models.ForeignKey(User, on_delete=models.PROTECT, related_name="hosted_sessions")
@@ -82,6 +83,7 @@ class RoundConfig(models.Model):
     points_bluff = models.IntegerField(default=2)
     lie_seconds = models.PositiveIntegerField(default=45)
     guess_seconds = models.PositiveIntegerField(default=30)
+    started_from_scoreboard = models.BooleanField(default=False)
 
     class Meta:
         unique_together = (("session", "number"),)

fupogfakta/payloads.py

@@ -0,0 +1,275 @@
+from datetime import timedelta
+
+from .models import GameSession, Player, RoundConfig, RoundQuestion
+
+
+def build_player_ref(player: Player | None) -> dict | None:
+    if player is None:
+        return None
+
+    return {
+        "player_id": player.id,
+        "nickname": player.nickname,
+    }
+
+
+def build_round_question_payload(round_question: RoundQuestion | None) -> dict | None:
+    if round_question is None:
+        return None
+
+    return {
+        "id": round_question.id,
+        "round_number": round_question.round_number,
+        "prompt": round_question.question.prompt,
+        "shown_at": round_question.shown_at.isoformat(),
+        "answers": [{"text": text} for text in (round_question.mixed_answers or [])],
+    }
+
+
+def build_reveal_payload(round_question: RoundQuestion | None) -> dict | None:
+    if round_question is None:
+        return None
+
+    lies = [
+        {
+            **build_player_ref(lie.player),
+            "text": lie.text,
+            "created_at": lie.created_at.isoformat(),
+        }
+        for lie in round_question.lies.select_related("player").order_by("created_at", "id")
+    ]
+
+    guesses = []
+    for guess in round_question.guesses.select_related("player", "fooled_player").order_by("created_at", "id"):
+        guess_payload = {
+            **build_player_ref(guess.player),
+            "selected_text": guess.selected_text,
+            "is_correct": guess.is_correct,
+            "created_at": guess.created_at.isoformat(),
+            "fooled_player_id": guess.fooled_player_id,
+        }
+        if guess.fooled_player is not None:
+            guess_payload["fooled_player_nickname"] = guess.fooled_player.nickname
+        guesses.append(guess_payload)
+
+    return {
+        "round_question_id": round_question.id,
+        "round_number": round_question.round_number,
+        "prompt": round_question.question.prompt,
+        "correct_answer": round_question.correct_answer,
+        "lies": lies,
+        "guesses": guesses,
+    }
+
+
+def build_leaderboard(session: GameSession) -> list[dict]:
+    return list(
+        Player.objects.filter(session=session)
+        .order_by("-score", "nickname")
+        .values("id", "nickname", "score")
+    )
+
+
+def build_lie_started_payload(session: GameSession, round_config: RoundConfig, round_question: RoundQuestion) -> dict:
+    lie_deadline_at = round_question.shown_at + timedelta(seconds=round_config.lie_seconds)
+    return {
+        "round_number": session.current_round,
+        "category": {"slug": round_config.category.slug, "name": round_config.category.name},
+        "round_question_id": round_question.id,
+        "prompt": round_question.question.prompt,
+        "shown_at": round_question.shown_at.isoformat(),
+        "lie_deadline_at": lie_deadline_at.isoformat(),
+        "lie_seconds": round_config.lie_seconds,
+    }
+
+
+def build_phase_view_model(session: GameSession, *, players_count: int, has_round_question: bool) -> dict:
+    status = session.status
+    in_lobby = status == GameSession.Status.LOBBY
+    in_lie = status == GameSession.Status.LIE
+    in_guess = status == GameSession.Status.GUESS
+    in_scoreboard = status == GameSession.Status.SCOREBOARD
+    in_finished = status == GameSession.Status.FINISHED
+
+    min_players_reached = players_count >= 3
+    max_players_allowed = players_count <= 5
+
+    return {
+        "status": status,
+        "current_phase": status,
+        "round_number": session.current_round,
+        "players_count": players_count,
+        "constraints": {
+            "min_players_to_start": 3,
+            "max_players_mvp": 5,
+            "min_players_reached": min_players_reached,
+            "max_players_allowed": max_players_allowed,
+        },
+        "readiness": {
+            "question_ready": has_round_question,
+            "scoreboard_ready": status in {GameSession.Status.REVEAL, GameSession.Status.SCOREBOARD, GameSession.Status.FINISHED},
+            "can_advance_to_next_round": in_scoreboard,
+        },
+        "host": {
+            "can_start_round": in_lobby and min_players_reached and max_players_allowed,
+            "can_show_question": False,
+            "can_mix_answers": False,
+            "can_calculate_scores": False,
+            "can_reveal_scoreboard": False,
+            "can_start_next_round": in_scoreboard,
+            "can_finish_game": in_scoreboard,
+        },
+        "player": {
+            "can_join": status in {
+                GameSession.Status.LOBBY,
+                GameSession.Status.LIE,
+                GameSession.Status.GUESS,
+                GameSession.Status.REVEAL,
+                GameSession.Status.SCOREBOARD,
+            },
+            "can_submit_lie": in_lie and has_round_question,
+            "can_submit_guess": in_guess and has_round_question,
+            "can_view_final_result": in_finished,
+        },
+    }
+
+
+def build_session_detail_gameplay_payload(
+    session: GameSession,
+    *,
+    current_round_question: RoundQuestion | None,
+    players_count: int,
+) -> dict:
+    return {
+        "round_question": build_round_question_payload(current_round_question),
+        "reveal": build_reveal_payload(current_round_question)
+        if session.status in {GameSession.Status.REVEAL, GameSession.Status.SCOREBOARD} and current_round_question
+        else None,
+        "scoreboard": build_scoreboard_phase_event(session)["payload"]["leaderboard"]
+        if session.status in {GameSession.Status.SCOREBOARD, GameSession.Status.FINISHED}
+        else None,
+        "phase_view_model": build_phase_view_model(
+            session,
+            players_count=players_count,
+            has_round_question=bool(current_round_question),
+        ),
+    }
+
+
+def build_start_round_response(
+    session: GameSession,
+    round_config: RoundConfig,
+    round_question: RoundQuestion,
+) -> dict:
+    lie_started_payload = build_lie_started_payload(session, round_config, round_question)
+    return {
+        "session": {
+            "code": session.code,
+            "status": session.status,
+            "current_round": session.current_round,
+        },
+        "round": {
+            "number": round_config.number,
+            "category": {
+                "slug": round_config.category.slug,
+                "name": round_config.category.name,
+            },
+        },
+        "round_question": {
+            "id": round_question.id,
+            "prompt": round_question.question.prompt,
+            "round_number": round_question.round_number,
+            "shown_at": round_question.shown_at.isoformat(),
+            "lie_deadline_at": lie_started_payload["lie_deadline_at"],
+        },
+        "config": {
+            "lie_seconds": round_config.lie_seconds,
+        },
+    }
+
+
+def build_question_shown_payload(round_question: RoundQuestion, lie_deadline_at: str, lie_seconds: int) -> dict:
+    return {
+        "round_question_id": round_question.id,
+        "prompt": round_question.question.prompt,
+        "shown_at": round_question.shown_at.isoformat(),
+        "lie_deadline_at": lie_deadline_at,
+        "lie_seconds": lie_seconds,
+    }
+
+
+def build_question_shown_response(round_question: RoundQuestion, lie_deadline_at: str, lie_seconds: int) -> dict:
+    return {
+        "round_question": {
+            "id": round_question.id,
+            "prompt": round_question.question.prompt,
+            "round_number": round_question.round_number,
+            "shown_at": round_question.shown_at.isoformat(),
+            "lie_deadline_at": lie_deadline_at,
+        },
+        "config": {
+            "lie_seconds": lie_seconds,
+        },
+    }
+
+
+def build_start_next_round_response(
+    session: GameSession,
+    round_config: RoundConfig,
+    round_question: RoundQuestion,
+) -> dict:
+    return build_start_round_response(session, round_config, round_question)
+
+
+def build_start_next_round_phase_event(
+    session: GameSession,
+    round_config: RoundConfig,
+    round_question: RoundQuestion,
+) -> dict:
+    return {
+        "name": "phase.lie_started",
+        "payload": build_lie_started_payload(session, round_config, round_question),
+    }
+
+
+def build_scoreboard_phase_event(session: GameSession, leaderboard: list[dict] | None = None) -> dict:
+    return {
+        "name": "phase.scoreboard",
+        "payload": {
+            "leaderboard": leaderboard if leaderboard is not None else build_leaderboard(session),
+            "current_round": session.current_round,
+        },
+    }
+
+
+def build_reveal_scoreboard_response(session: GameSession, leaderboard: list[dict]) -> dict:
+    return {
+        "session": {
+            "code": session.code,
+            "status": session.status,
+            "current_round": session.current_round,
+        },
+        "leaderboard": leaderboard,
+    }
+
+
+def build_finish_game_phase_event(session: GameSession) -> dict:
+    leaderboard = build_leaderboard(session)
+    winner = leaderboard[0] if leaderboard else None
+    return {
+        "name": "phase.game_over",
+        "payload": {"winner": winner, "leaderboard": leaderboard},
+    }
+
+
+def build_finish_game_response(session: GameSession) -> dict:
+    finish_event = build_finish_game_phase_event(session)
+    return {
+        "session": {
+            "code": session.code,
+            "status": GameSession.Status.FINISHED,
+            "current_round": session.current_round,
+        },
+        "winner": finish_event["payload"]["winner"],
+        "leaderboard": finish_event["payload"]["leaderboard"],
+    }

fupogfakta/services.py

@@ -0,0 +1,479 @@
+import random
+from datetime import timedelta
+from dataclasses import dataclass
+from typing import Any
+
+from django.db import transaction
+from django.utils import timezone
+
+from .models import Category, GameSession, Guess, LieAnswer, Player, Question, RoundConfig, RoundQuestion, ScoreEvent
+from .payloads import (
+    build_finish_game_phase_event,
+    build_finish_game_response,
+    build_lie_started_payload,
+    build_question_shown_payload,
+    build_question_shown_response,
+    build_reveal_scoreboard_response,
+    build_scoreboard_phase_event,
+    build_start_next_round_phase_event,
+    build_start_next_round_response,
+    build_start_round_response,
+)
+
+
+@dataclass(frozen=True)
+class RoundTransitionResult:
+    session: GameSession
+    round_config: RoundConfig
+    round_question: RoundQuestion
+    should_broadcast: bool
+    response_payload: dict[str, Any]
+    phase_event_name: str | None = None
+    phase_event_payload: dict[str, Any] | None = None
+
+
+@dataclass(frozen=True)
+class FinishGameResult:
+    session: GameSession
+    should_broadcast: bool
+    response_payload: dict[str, Any]
+    phase_event_name: str | None = None
+    phase_event_payload: dict[str, Any] | None = None
+
+
+@dataclass(frozen=True)
+class ScoreboardTransitionResult:
+    session: GameSession
+    leaderboard: list[dict]
+    should_broadcast: bool
+    response_payload: dict[str, Any] | None = None
+    phase_event_name: str | None = None
+    phase_event_payload: dict[str, Any] | None = None
+
+
+def get_round_question(session: GameSession, round_number: int) -> RoundQuestion | None:
+    return (
+        RoundQuestion.objects.filter(session=session, round_number=round_number)
+        .select_related("question")
+        .order_by("-id")
+        .first()
+    )
+
+
+
+def get_current_round_question(session: GameSession) -> RoundQuestion | None:
+    return get_round_question(session, session.current_round)
+
+
+
+def reset_round_question_bootstrap_state(round_question: RoundQuestion) -> RoundQuestion:
+    Guess.objects.filter(round_question=round_question).delete()
+    LieAnswer.objects.filter(round_question=round_question).delete()
+
+    update_fields: list[str] = []
+    if round_question.mixed_answers:
+        round_question.mixed_answers = []
+        update_fields.append("mixed_answers")
+
+    round_question.shown_at = timezone.now()
+    update_fields.append("shown_at")
+
+    round_question.save(update_fields=update_fields)
+    return round_question
+
+
+
+def select_round_question(
+    session: GameSession,
+    round_config: RoundConfig,
+    *,
+    round_number: int | None = None,
+) -> RoundQuestion:
+    target_round_number = session.current_round if round_number is None else round_number
+    existing_round_question = get_round_question(session, target_round_number)
+    if existing_round_question is not None and existing_round_question.question.category_id == round_config.category_id:
+        return existing_round_question
+
+    used_question_ids = RoundQuestion.objects.filter(session=session).values_list("question_id", flat=True)
+    available_questions = Question.objects.filter(
+        category=round_config.category,
+        is_active=True,
+    ).exclude(pk__in=used_question_ids)
+
+    if not available_questions.exists():
+        raise ValueError("no_available_questions")
+
+    question = random.choice(list(available_questions))
+    if existing_round_question is not None:
+        existing_round_question.question = question
+        existing_round_question.correct_answer = question.correct_answer
+        existing_round_question.save(update_fields=["question", "correct_answer"])
+        return existing_round_question
+
+    return RoundQuestion.objects.create(
+        session=session,
+        round_number=target_round_number,
+        question=question,
+        correct_answer=question.correct_answer,
+    )
+
+
+
+def prepare_mixed_answers(round_question: RoundQuestion) -> list[str]:
+    deduped_answers = list(round_question.mixed_answers or [])
+    if deduped_answers:
+        return deduped_answers
+
+    lie_texts = list(round_question.lies.values_list("text", flat=True))
+    seen = set()
+    for text in [round_question.correct_answer, *lie_texts]:
+        normalized = text.strip().casefold()
+        if not normalized or normalized in seen:
+            continue
+        seen.add(normalized)
+        deduped_answers.append(text.strip())
+
+    if len(deduped_answers) < 2:
+        raise ValueError("not_enough_answers_to_mix")
+
+    random.shuffle(deduped_answers)
+    round_question.mixed_answers = deduped_answers
+    round_question.save(update_fields=["mixed_answers"])
+    return deduped_answers
+
+
+
+
+
+def start_round(session: GameSession, category_slug: str) -> RoundTransitionResult:
+    try:
+        category = Category.objects.get(slug=category_slug, is_active=True)
+    except Category.DoesNotExist:
+        raise ValueError("category_not_found")
+
+    if not Question.objects.filter(category=category, is_active=True).exists():
+        raise ValueError("category_has_no_questions")
+
+    with transaction.atomic():
+        locked_session = GameSession.objects.select_for_update().get(pk=session.pk)
+        if locked_session.status != GameSession.Status.LOBBY:
+            raise ValueError("round_start_invalid_phase")
+
+        if RoundConfig.objects.filter(session=locked_session, number=locked_session.current_round).exists():
+            raise ValueError("round_already_configured")
+
+        round_config = RoundConfig(
+            session=locked_session,
+            number=locked_session.current_round,
+            category=category,
+        )
+
+        round_question = select_round_question(locked_session, round_config)
+
+        round_config.save()
+        locked_session.status = GameSession.Status.LIE
+        locked_session.save(update_fields=["status"])
+
+    phase_event = {
+        "name": "phase.lie_started",
+        "payload": build_lie_started_payload(locked_session, round_config, round_question),
+    }
+    return RoundTransitionResult(
+        session=locked_session,
+        round_config=round_config,
+        round_question=round_question,
+        should_broadcast=True,
+        response_payload=build_start_round_response(locked_session, round_config, round_question),
+        phase_event_name=phase_event["name"],
+        phase_event_payload=phase_event["payload"],
+    )
+
+
+def show_question(session: GameSession) -> RoundTransitionResult:
+    if session.status != GameSession.Status.LIE:
+        raise ValueError("show_question_invalid_phase")
+
+    try:
+        round_config = RoundConfig.objects.get(session=session, number=session.current_round)
+    except RoundConfig.DoesNotExist:
+        raise ValueError("round_config_missing")
+
+    round_question = get_current_round_question(session)
+    if round_question is None:
+        round_question = select_round_question(session, round_config)
+
+    lie_deadline_at = round_question.shown_at + timedelta(seconds=round_config.lie_seconds)
+    lie_deadline_iso = lie_deadline_at.isoformat()
+    phase_event = {
+        "name": "phase.question_shown",
+        "payload": build_question_shown_payload(round_question, lie_deadline_iso, round_config.lie_seconds),
+    }
+    return RoundTransitionResult(
+        session=session,
+        round_config=round_config,
+        round_question=round_question,
+        should_broadcast=True,
+        response_payload=build_question_shown_response(round_question, lie_deadline_iso, round_config.lie_seconds),
+        phase_event_name=phase_event["name"],
+        phase_event_payload=phase_event["payload"],
+    )
+
+def start_next_round(session: GameSession) -> RoundTransitionResult:
+    with transaction.atomic():
+        locked_session = GameSession.objects.select_for_update().get(pk=session.pk)
+        next_round_config = None
+        round_question = None
+        should_broadcast = False
+
+        phase_event_name = None
+        phase_event_payload = None
+
+        if locked_session.status == GameSession.Status.SCOREBOARD:
+            previous_round_config = RoundConfig.objects.filter(
+                session=locked_session,
+                number=locked_session.current_round,
+            ).select_related("category").first()
+            if previous_round_config is None:
+                raise ValueError("round_config_missing")
+
+            next_round_number = locked_session.current_round + 1
+            next_round_config, _created = RoundConfig.objects.get_or_create(
+                session=locked_session,
+                number=next_round_number,
+                defaults={
+                    "category": previous_round_config.category,
+                    "lie_seconds": previous_round_config.lie_seconds,
+                    "guess_seconds": previous_round_config.guess_seconds,
+                    "points_correct": previous_round_config.points_correct,
+                    "points_bluff": previous_round_config.points_bluff,
+                    "started_from_scoreboard": True,
+                },
+            )
+            round_config_update_fields: list[str] = []
+            if next_round_config.category_id != previous_round_config.category_id:
+                next_round_config.category = previous_round_config.category
+                round_config_update_fields.append("category")
+            if next_round_config.lie_seconds != previous_round_config.lie_seconds:
+                next_round_config.lie_seconds = previous_round_config.lie_seconds
+                round_config_update_fields.append("lie_seconds")
+            if next_round_config.guess_seconds != previous_round_config.guess_seconds:
+                next_round_config.guess_seconds = previous_round_config.guess_seconds
+                round_config_update_fields.append("guess_seconds")
+            if next_round_config.points_correct != previous_round_config.points_correct:
+                next_round_config.points_correct = previous_round_config.points_correct
+                round_config_update_fields.append("points_correct")
+            if next_round_config.points_bluff != previous_round_config.points_bluff:
+                next_round_config.points_bluff = previous_round_config.points_bluff
+                round_config_update_fields.append("points_bluff")
+            if not next_round_config.started_from_scoreboard:
+                next_round_config.started_from_scoreboard = True
+                round_config_update_fields.append("started_from_scoreboard")
+            if round_config_update_fields:
+                next_round_config.save(update_fields=round_config_update_fields)
+
+            locked_session.current_round = next_round_number
+
+            round_question = reset_round_question_bootstrap_state(
+                select_round_question(locked_session, next_round_config, round_number=next_round_number)
+            )
+
+            locked_session.status = GameSession.Status.LIE
+            locked_session.save(update_fields=["current_round", "status"])
+            should_broadcast = True
+            phase_event = build_start_next_round_phase_event(locked_session, next_round_config, round_question)
+            phase_event_name = phase_event["name"]
+            phase_event_payload = phase_event["payload"]
+        elif locked_session.status == GameSession.Status.LIE:
+            if locked_session.current_round <= 1:
+                raise ValueError("next_round_invalid_phase")
+
+            next_round_config = RoundConfig.objects.filter(
+                session=locked_session,
+                number=locked_session.current_round,
+            ).select_related("category").first()
+            round_question = get_current_round_question(locked_session)
+            if (
+                next_round_config is None
+                or not next_round_config.started_from_scoreboard
+                or round_question is None
+            ):
+                raise ValueError("next_round_invalid_phase")
+        else:
+            raise ValueError("next_round_invalid_phase")
+
+        return RoundTransitionResult(
+            session=locked_session,
+            round_config=next_round_config,
+            round_question=round_question,
+            should_broadcast=should_broadcast,
+            response_payload=build_start_next_round_response(
+                locked_session,
+                next_round_config,
+                round_question,
+            ),
+            phase_event_name=phase_event_name,
+            phase_event_payload=phase_event_payload,
+        )
+
+
+
+def finish_game(session: GameSession) -> FinishGameResult:
+    with transaction.atomic():
+        locked_session = GameSession.objects.select_for_update().get(pk=session.pk)
+        should_broadcast = False
+        phase_event_name = None
+        phase_event_payload = None
+
+        if locked_session.status == GameSession.Status.SCOREBOARD:
+            locked_session.status = GameSession.Status.FINISHED
+            locked_session.save(update_fields=["status"])
+            should_broadcast = True
+            phase_event = build_finish_game_phase_event(locked_session)
+            phase_event_name = phase_event["name"]
+            phase_event_payload = phase_event["payload"]
+        elif locked_session.status != GameSession.Status.FINISHED:
+            raise ValueError("finish_game_invalid_phase")
+
+        return FinishGameResult(
+            session=locked_session,
+            should_broadcast=should_broadcast,
+            response_payload=build_finish_game_response(locked_session),
+            phase_event_name=phase_event_name,
+            phase_event_payload=phase_event_payload,
+        )
+
+
+
+def promote_reveal_to_scoreboard(session: GameSession) -> ScoreboardTransitionResult:
+    if session.status != GameSession.Status.REVEAL:
+        leaderboard = list(
+            Player.objects.filter(session=session)
+            .order_by("-score", "nickname")
+            .values("id", "nickname", "score")
+        )
+        return ScoreboardTransitionResult(
+            session=session,
+            leaderboard=leaderboard,
+            should_broadcast=False,
+            response_payload=build_reveal_scoreboard_response(session, leaderboard),
+        )
+
+    current_round_question = get_current_round_question(session)
+    if current_round_question is None:
+        leaderboard = list(
+            Player.objects.filter(session=session)
+            .order_by("-score", "nickname")
+            .values("id", "nickname", "score")
+        )
+        return ScoreboardTransitionResult(
+            session=session,
+            leaderboard=leaderboard,
+            should_broadcast=False,
+            response_payload=build_reveal_scoreboard_response(session, leaderboard),
+        )
+
+    players_count = Player.objects.filter(session=session).count()
+    guess_count = Guess.objects.filter(round_question=current_round_question).count()
+    has_score_events = ScoreEvent.objects.filter(
+        session=session,
+        meta__round_question_id=current_round_question.id,
+    ).exists()
+    reveal_is_resolved = has_score_events or (players_count > 0 and guess_count >= players_count)
+    if not reveal_is_resolved:
+        leaderboard = list(
+            Player.objects.filter(session=session)
+            .order_by("-score", "nickname")
+            .values("id", "nickname", "score")
+        )
+        return ScoreboardTransitionResult(
+            session=session,
+            leaderboard=leaderboard,
+            should_broadcast=False,
+            response_payload=build_reveal_scoreboard_response(session, leaderboard),
+        )
+
+    with transaction.atomic():
+        locked_session = GameSession.objects.select_for_update().get(pk=session.pk)
+        if locked_session.status != GameSession.Status.REVEAL:
+            scoreboard_session = locked_session
+            should_broadcast = False
+        else:
+            locked_session.status = GameSession.Status.SCOREBOARD
+            locked_session.save(update_fields=["status"])
+            scoreboard_session = locked_session
+            should_broadcast = True
+
+    leaderboard = list(
+        Player.objects.filter(session=scoreboard_session)
+        .order_by("-score", "nickname")
+        .values("id", "nickname", "score")
+    )
+    phase_event_name = None
+    phase_event_payload = None
+    if should_broadcast:
+        phase_event = build_scoreboard_phase_event(scoreboard_session, leaderboard)
+        phase_event_name = phase_event["name"]
+        phase_event_payload = phase_event["payload"]
+    return ScoreboardTransitionResult(
+        session=scoreboard_session,
+        leaderboard=leaderboard,
+        should_broadcast=should_broadcast,
+        response_payload=build_reveal_scoreboard_response(scoreboard_session, leaderboard),
+        phase_event_name=phase_event_name,
+        phase_event_payload=phase_event_payload,
+    )
+
+
+
+def resolve_scores(
+    session: GameSession,
+    round_question: RoundQuestion,
+    round_config: RoundConfig,
+) -> tuple[list[ScoreEvent], list[dict]]:
+    guesses = list(round_question.guesses.select_related("player"))
+    if not guesses:
+        raise ValueError("no_guesses_submitted")
+
+    bluff_counts: dict[int, int] = {}
+    for guess in guesses:
+        if guess.fooled_player_id:
+            bluff_counts[guess.fooled_player_id] = bluff_counts.get(guess.fooled_player_id, 0) + 1
+
+    score_events = []
+
+    for guess in guesses:
+        if guess.is_correct:
+            guess.player.score += round_config.points_correct
+            guess.player.save(update_fields=["score"])
+            score_events.append(
+                ScoreEvent(
+                    session=session,
+                    player=guess.player,
+                    delta=round_config.points_correct,
+                    reason="guess_correct",
+                    meta={"round_question_id": round_question.id, "guess_id": guess.id},
+                )
+            )
+
+    for player_id, fooled_count in bluff_counts.items():
+        delta = fooled_count * round_config.points_bluff
+        player = Player.objects.get(pk=player_id, session=session)
+        player.score += delta
+        player.save(update_fields=["score"])
+        score_events.append(
+            ScoreEvent(
+                session=session,
+                player=player,
+                delta=delta,
+                reason="bluff_success",
+                meta={"round_question_id": round_question.id, "fooled_count": fooled_count},
+            )
+        )
+
+    ScoreEvent.objects.bulk_create(score_events)
+    leaderboard = list(
+        Player.objects.filter(session=session)
+        .order_by("-score", "nickname")
+        .values("id", "nickname", "score")
+    )
+    return score_events, leaderboard

fupogfakta/tests.py

@@ -1,2 +1,410 @@
+from datetime import timedelta
+from unittest.mock import patch
 
-# Create your tests here.
+from django.contrib.auth import get_user_model
+from django.test import TestCase
+from django.utils import timezone
+
+from fupogfakta.models import Category, GameSession, Guess, LieAnswer, Player, Question, RoundConfig, RoundQuestion, ScoreEvent
+from fupogfakta.payloads import (
+    build_lie_started_payload,
+    build_phase_view_model,
+    build_reveal_payload,
+    build_round_question_payload,
+    build_session_detail_gameplay_payload,
+)
+from fupogfakta.services import (
+    finish_game,
+    get_current_round_question,
+    prepare_mixed_answers,
+    promote_reveal_to_scoreboard,
+    resolve_scores,
+    select_round_question,
+    start_next_round,
+)
+
+User = get_user_model()
+
+
+class FupOgFaktaExtractionSliceTests(TestCase):
+    def setUp(self):
+        self.host = User.objects.create_user(username="host", password="secret123")
+        self.session = GameSession.objects.create(host=self.host, code="ABCD23")
+        self.category = Category.objects.create(name="Historie", slug="historie", is_active=True)
+        self.question_one = Question.objects.create(
+            category=self.category,
+            prompt="Hvornår faldt muren?",
+            correct_answer="1989",
+            is_active=True,
+        )
+        self.question_two = Question.objects.create(
+            category=self.category,
+            prompt="Hvornår kom euroen?",
+            correct_answer="1999",
+            is_active=True,
+        )
+        self.round_config = RoundConfig.objects.create(session=self.session, number=1, category=self.category)
+        self.alice = Player.objects.create(session=self.session, nickname="Alice")
+        self.bob = Player.objects.create(session=self.session, nickname="Bob")
+        self.clara = Player.objects.create(session=self.session, nickname="Clara")
+
+    def test_select_round_question_skips_already_used_questions_for_session(self):
+        RoundQuestion.objects.create(
+            session=self.session,
+            round_number=99,
+            question=self.question_one,
+            correct_answer=self.question_one.correct_answer,
+        )
+
+        round_question = select_round_question(self.session, self.round_config)
+
+        self.assertEqual(round_question.question, self.question_two)
+        self.assertEqual(get_current_round_question(self.session), round_question)
+
+    def test_prepare_mixed_answers_dedupes_blank_and_case_variants(self):
+        round_question = RoundQuestion.objects.create(
+            session=self.session,
+            round_number=1,
+            question=self.question_one,
+            correct_answer="1989",
+        )
+        LieAnswer.objects.create(round_question=round_question, player=self.alice, text=" 1989 ")
+        LieAnswer.objects.create(round_question=round_question, player=self.bob, text="Nitten niogfirs")
+        LieAnswer.objects.create(round_question=round_question, player=self.clara, text="   ")
+
+        with patch("fupogfakta.services.random.shuffle", side_effect=lambda answers: None):
+            answers = prepare_mixed_answers(round_question)
+
+        self.assertEqual(answers, ["1989", "Nitten niogfirs"])
+        round_question.refresh_from_db()
+        self.assertEqual(round_question.mixed_answers, answers)
+
+    def test_start_next_round_moves_scoreboard_transition_into_service(self):
+        self.session.status = GameSession.Status.SCOREBOARD
+        self.session.save(update_fields=["status"])
+
+        result = start_next_round(self.session)
+
+        self.session.refresh_from_db()
+        self.assertTrue(result.should_broadcast)
+        self.assertEqual(result.session.status, GameSession.Status.LIE)
+        self.assertEqual(result.session.current_round, 2)
+        self.assertEqual(result.round_config.number, 2)
+        self.assertTrue(result.round_config.started_from_scoreboard)
+        self.assertEqual(result.round_question.round_number, 2)
+
+    def test_start_next_round_rejects_plain_lie_without_scoreboard_marker(self):
+        self.session.status = GameSession.Status.LIE
+        self.session.current_round = 2
+        self.session.save(update_fields=["status", "current_round"])
+        RoundConfig.objects.create(session=self.session, number=2, category=self.category, started_from_scoreboard=False)
+        RoundQuestion.objects.create(
+            session=self.session,
+            round_number=2,
+            question=self.question_two,
+            correct_answer=self.question_two.correct_answer,
+        )
+
+        with self.assertRaisesMessage(ValueError, "next_round_invalid_phase"):
+            start_next_round(self.session)
+
+    def test_start_next_round_refreshes_shown_at_for_reused_bootstrap_question(self):
+        self.session.status = GameSession.Status.SCOREBOARD
+        self.session.save(update_fields=["status"])
+        stale_shown_at = timezone.now() - timedelta(minutes=10)
+        stale_round_question = RoundQuestion.objects.create(
+            session=self.session,
+            round_number=2,
+            question=self.question_two,
+            correct_answer=self.question_two.correct_answer,
+            shown_at=stale_shown_at,
+            mixed_answers=["Stale truth", "Stale lie"],
+        )
+        LieAnswer.objects.create(round_question=stale_round_question, player=self.alice, text="Stale lie")
+        Guess.objects.create(
+            round_question=stale_round_question,
+            player=self.bob,
+            selected_text="Stale truth",
+            is_correct=True,
+        )
+
+        before_transition = timezone.now()
+        result = start_next_round(self.session)
+        after_transition = timezone.now()
+
+        stale_round_question.refresh_from_db()
+        self.assertEqual(result.round_question.id, stale_round_question.id)
+        self.assertGreaterEqual(stale_round_question.shown_at, before_transition)
+        self.assertLessEqual(stale_round_question.shown_at, after_transition)
+        self.assertNotEqual(stale_round_question.shown_at, stale_shown_at)
+        self.assertEqual(result.response_payload["round_question"]["shown_at"], stale_round_question.shown_at.isoformat())
+        expected_deadline = stale_round_question.shown_at + timedelta(seconds=result.round_config.lie_seconds)
+        self.assertEqual(result.response_payload["round_question"]["lie_deadline_at"], expected_deadline.isoformat())
+        self.assertGreater(expected_deadline, before_transition)
+        self.assertEqual(stale_round_question.mixed_answers, [])
+        self.assertEqual(stale_round_question.lies.count(), 0)
+        self.assertEqual(stale_round_question.guesses.count(), 0)
+
+    def test_start_next_round_reuses_existing_bootstrap_round_config_with_fresh_canonical_values(self):
+        self.session.status = GameSession.Status.SCOREBOARD
+        self.session.save(update_fields=["status"])
+        stale_category = Category.objects.create(name="Sport", slug="sport", is_active=True)
+        stale_round_config = RoundConfig.objects.create(
+            session=self.session,
+            number=2,
+            category=stale_category,
+            lie_seconds=12,
+            guess_seconds=18,
+            points_correct=9,
+            points_bluff=7,
+            started_from_scoreboard=False,
+        )
+        stale_round_question = RoundQuestion.objects.create(
+            session=self.session,
+            round_number=2,
+            question=self.question_two,
+            correct_answer=self.question_two.correct_answer,
+            shown_at=timezone.now() - timedelta(minutes=10),
+            mixed_answers=["Stale truth"],
+        )
+
+        result = start_next_round(self.session)
+
+        stale_round_config.refresh_from_db()
+        stale_round_question.refresh_from_db()
+        self.assertEqual(result.round_config.id, stale_round_config.id)
+        self.assertEqual(RoundConfig.objects.filter(session=self.session, number=2).count(), 1)
+        self.assertEqual(stale_round_config.category_id, self.round_config.category_id)
+        self.assertEqual(stale_round_config.lie_seconds, self.round_config.lie_seconds)
+        self.assertEqual(stale_round_config.guess_seconds, self.round_config.guess_seconds)
+        self.assertEqual(stale_round_config.points_correct, self.round_config.points_correct)
+        self.assertEqual(stale_round_config.points_bluff, self.round_config.points_bluff)
+        self.assertTrue(stale_round_config.started_from_scoreboard)
+        self.assertEqual(result.round_question.id, stale_round_question.id)
+        self.assertEqual(stale_round_question.mixed_answers, [])
+
+    def test_start_next_round_repairs_reused_bootstrap_question_when_category_drifted(self):
+        self.session.status = GameSession.Status.SCOREBOARD
+        self.session.save(update_fields=["status"])
+        RoundQuestion.objects.create(
+            session=self.session,
+            round_number=1,
+            question=self.question_one,
+            correct_answer=self.question_one.correct_answer,
+        )
+        stale_category = Category.objects.create(name="Sport drift", slug="sport-drift", is_active=True)
+        stale_question = Question.objects.create(
+            category=stale_category,
+            prompt="Hvem vandt EM i 1992?",
+            correct_answer="Danmark",
+            is_active=True,
+        )
+        stale_round_question = RoundQuestion.objects.create(
+            session=self.session,
+            round_number=2,
+            question=stale_question,
+            correct_answer=stale_question.correct_answer,
+            shown_at=timezone.now() - timedelta(minutes=10),
+            mixed_answers=["Stale truth", "Stale lie"],
+        )
+        LieAnswer.objects.create(round_question=stale_round_question, player=self.alice, text="Tyskland")
+        Guess.objects.create(
+            round_question=stale_round_question,
+            player=self.bob,
+            selected_text="Stale truth",
+            is_correct=True,
+        )
+
+        result = start_next_round(self.session)
+
+        stale_round_question.refresh_from_db()
+        self.assertEqual(result.round_question.id, stale_round_question.id)
+        self.assertEqual(stale_round_question.question.category_id, self.round_config.category_id)
+        self.assertEqual(stale_round_question.question_id, self.question_two.id)
+        self.assertEqual(stale_round_question.correct_answer, self.question_two.correct_answer)
+        self.assertEqual(stale_round_question.mixed_answers, [])
+        self.assertEqual(stale_round_question.lies.count(), 0)
+        self.assertEqual(stale_round_question.guesses.count(), 0)
+
+    def test_start_next_round_does_not_reuse_previous_round_question_when_category_matches(self):
+        self.session.status = GameSession.Status.SCOREBOARD
+        self.session.save(update_fields=["status"])
+        previous_round_question = RoundQuestion.objects.create(
+            session=self.session,
+            round_number=1,
+            question=self.question_one,
+            correct_answer=self.question_one.correct_answer,
+            mixed_answers=["1989", "1991"],
+        )
+        LieAnswer.objects.create(round_question=previous_round_question, player=self.alice, text="1991")
+        Guess.objects.create(
+            round_question=previous_round_question,
+            player=self.bob,
+            selected_text="1991",
+            is_correct=False,
+            fooled_player=self.alice,
+        )
+
+        result = start_next_round(self.session)
+
+        previous_round_question.refresh_from_db()
+        self.session.refresh_from_db()
+        self.assertEqual(self.session.current_round, 2)
+        self.assertEqual(result.round_question.round_number, 2)
+        self.assertNotEqual(result.round_question.id, previous_round_question.id)
+        self.assertEqual(result.round_question.question_id, self.question_two.id)
+        self.assertEqual(previous_round_question.round_number, 1)
+        self.assertEqual(previous_round_question.question_id, self.question_one.id)
+        self.assertEqual(previous_round_question.mixed_answers, ["1989", "1991"])
+        self.assertEqual(previous_round_question.lies.count(), 1)
+        self.assertEqual(previous_round_question.guesses.count(), 1)
+
+    def test_finish_game_moves_scoreboard_transition_into_service(self):
+        self.session.status = GameSession.Status.SCOREBOARD
+        self.session.save(update_fields=["status"])
+
+        result = finish_game(self.session)
+
+        self.session.refresh_from_db()
+        self.assertTrue(result.should_broadcast)
+        self.assertEqual(result.session.status, GameSession.Status.FINISHED)
+        self.assertEqual(self.session.status, GameSession.Status.FINISHED)
+
+    def test_promote_reveal_to_scoreboard_moves_transition_into_service(self):
+        round_question = RoundQuestion.objects.create(
+            session=self.session,
+            round_number=1,
+            question=self.question_one,
+            correct_answer=self.question_one.correct_answer,
+        )
+        self.session.status = GameSession.Status.REVEAL
+        self.session.save(update_fields=["status"])
+
+        LieAnswer.objects.create(round_question=round_question, player=self.alice, text="Elbil")
+        Guess.objects.create(
+            round_question=round_question,
+            player=self.bob,
+            selected_text="Elbil",
+            is_correct=False,
+            fooled_player=self.alice,
+        )
+        ScoreEvent.objects.create(
+            session=self.session,
+            player=self.alice,
+            delta=5,
+            reason="bluff_success",
+            meta={"round_question_id": round_question.id},
+        )
+        self.alice.score = 5
+        self.alice.save(update_fields=["score"])
+
+        result = promote_reveal_to_scoreboard(self.session)
+
+        self.session.refresh_from_db()
+        self.assertTrue(result.should_broadcast)
+        self.assertEqual(result.session.status, GameSession.Status.SCOREBOARD)
+        self.assertEqual(result.leaderboard[0]["nickname"], self.alice.nickname)
+
+    def test_resolve_scores_applies_correct_and_bluff_points(self):
+        round_question = RoundQuestion.objects.create(
+            session=self.session,
+            round_number=1,
+            question=self.question_one,
+            correct_answer="1989",
+        )
+        Guess.objects.create(
+            round_question=round_question,
+            player=self.alice,
+            selected_text="1989",
+            is_correct=True,
+        )
+        Guess.objects.create(
+            round_question=round_question,
+            player=self.bob,
+            selected_text="Berlin",
+            is_correct=False,
+            fooled_player=self.clara,
+        )
+        Guess.objects.create(
+            round_question=round_question,
+            player=self.clara,
+            selected_text="Berlin",
+            is_correct=False,
+            fooled_player=self.clara,
+        )
+
+        score_events, leaderboard = resolve_scores(self.session, round_question, self.round_config)
+
+        self.assertEqual(len(score_events), 2)
+        self.alice.refresh_from_db()
+        self.clara.refresh_from_db()
+        self.assertEqual(self.alice.score, self.round_config.points_correct)
+        self.assertEqual(self.clara.score, self.round_config.points_bluff * 2)
+        self.assertEqual(ScoreEvent.objects.filter(session=self.session, meta__round_question_id=round_question.id).count(), 2)
+        self.assertEqual([entry["nickname"] for entry in leaderboard], ["Alice", "Clara", "Bob"])
+
+    def test_payload_builders_expose_fupogfakta_round_contract(self):
+        round_question = RoundQuestion.objects.create(
+            session=self.session,
+            round_number=1,
+            question=self.question_one,
+            correct_answer="1989",
+        )
+        lie = LieAnswer.objects.create(round_question=round_question, player=self.bob, text="1991")
+        Guess.objects.create(
+            round_question=round_question,
+            player=self.alice,
+            selected_text="1991",
+            is_correct=False,
+            fooled_player=self.bob,
+        )
+
+        round_question_payload = build_round_question_payload(round_question)
+        lie_payload = build_lie_started_payload(self.session, self.round_config, round_question)
+        reveal_payload = build_reveal_payload(round_question)
+        phase_view_model = build_phase_view_model(
+            self.session,
+            players_count=3,
+            has_round_question=True,
+        )
+
+        self.assertEqual(round_question_payload["prompt"], self.question_one.prompt)
+        self.assertEqual(round_question_payload["answers"], [])
+        self.assertEqual(lie_payload["category"], {"slug": self.category.slug, "name": self.category.name})
+        self.assertEqual(lie_payload["round_question_id"], round_question.id)
+        self.assertEqual(reveal_payload["correct_answer"], "1989")
+        self.assertEqual(reveal_payload["lies"][0]["player_id"], lie.player_id)
+        self.assertEqual(reveal_payload["guesses"][0]["fooled_player_nickname"], self.bob.nickname)
+        self.assertTrue(phase_view_model["host"]["can_start_round"])
+        self.assertFalse(phase_view_model["host"]["can_finish_game"])
+
+    def test_build_session_detail_gameplay_payload_keeps_session_detail_semantics_in_cartridge(self):
+        self.session.status = GameSession.Status.SCOREBOARD
+        self.session.save(update_fields=["status"])
+        round_question = RoundQuestion.objects.create(
+            session=self.session,
+            round_number=1,
+            question=self.question_one,
+            correct_answer=self.question_one.correct_answer,
+        )
+        lie = LieAnswer.objects.create(round_question=round_question, player=self.bob, text="1991")
+        Guess.objects.create(
+            round_question=round_question,
+            player=self.alice,
+            selected_text="1991",
+            is_correct=False,
+            fooled_player=self.bob,
+        )
+
+        gameplay_payload = build_session_detail_gameplay_payload(
+            self.session,
+            current_round_question=round_question,
+            players_count=3,
+        )
+
+        self.assertEqual(gameplay_payload["round_question"]["id"], round_question.id)
+        self.assertEqual(gameplay_payload["reveal"]["lies"][0]["player_id"], lie.player_id)
+        self.assertEqual(gameplay_payload["scoreboard"], [{"id": self.alice.id, "nickname": self.alice.nickname, "score": self.alice.score}, {"id": self.bob.id, "nickname": self.bob.nickname, "score": self.bob.score}, {"id": self.clara.id, "nickname": self.clara.nickname, "score": self.clara.score}])
+        self.assertEqual(gameplay_payload["phase_view_model"]["status"], GameSession.Status.SCOREBOARD)
+        self.assertTrue(gameplay_payload["phase_view_model"]["host"]["can_start_next_round"])
+        self.assertTrue(gameplay_payload["phase_view_model"]["host"]["can_finish_game"])