feat: add canonical reveal payload for issue 289

Auto-merge by integrator: required checks green + official approval.

.gitea/workflows/ci.yml

@@ -0,0 +1,44 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - "**"
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  test-and-quality:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -r requirements.txt
+          pip install ruff
+
+      - name: Lint
+        run: ruff check lobby
+
+      - 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
+
+      - name: SPA Angular smoke tests
+        run: npm --prefix frontend/angular test

.gitignore

@@ -22,6 +22,7 @@ media/
 .env
 .env.*
 !.env.test.example
+!.env.staging.example
 !.env.prod.example
 
 # Editors/OS

TODO.md

@@ -14,7 +14,7 @@ Byg **Weirsøe Party Protocol**: en dansk party-webapp platform ala Jackbox, hvo
 - Deployment: Proxmox LXC (ikke Docker)
 
 ## Midlertidige defaults (kan finjusteres senere)
-- Spillere: min 3, max 12
+- Spillere: min 3, default max 5 (MVP)
 - Løgntid (X): 45 sek
 - Gættetid (Z): 30 sek
 - Login: username/password for host/admin
@@ -29,7 +29,7 @@ Byg **Weirsøe Party Protocol**: en dansk party-webapp platform ala Jackbox, hvo
 ### Fase 0 — Scope + regler
 - [x] Fastlæg MVP for Spil 1 (`Fup og Fakta`) — se `docs/F0_MVP_FUP_OG_FAKTA.md`
 - [x] Midlertidige defaults sat (X/Z, spillerantal)
-- [ ] Fastlæg anti-cheat regler (fx ingen identiske løgne)
+- [x] Fastlæg anti-cheat regler (fx ingen identiske løgne) — se docs/F0_ANTI_CHEAT_RULES.md
 
 ### Fase 1 — Monorepo + Django skelet
 - [x] Opret Django-projekt (`partyhub`)
@@ -53,14 +53,14 @@ Byg **Weirsøe Party Protocol**: en dansk party-webapp platform ala Jackbox, hvo
 - [x] `ScoreEvent` (auditérbar pointslog)
 
 ### Fase 3 — Spilflow `Fup og Fakta`
-- [ ] Lobby: host opretter session, spillere joiner via kode
-- [ ] Runde starter med kategori
-- [ ] Spørgsmål vises -> alle skriver løgn inden X sek
-- [ ] System blander korrekt svar + løgne
-- [ ] Guessfase: alle gætter inden Z sek
-- [ ] Pointudregning (konfigurerbar pr. runde)
-- [ ] Scoreboard + næste spørgsmål/runde
-- [ ] Slutresultat
+- [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
 
 ### Fase 4 — Voice-acting (platformkrav)
 - [ ] Definér TTS provider-interface
@@ -103,9 +103,21 @@ 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) 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.
+- [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)
 - [ ] (Nice-to-have) Runde-tema musik/lyd-cues
 - [ ] (Nice-to-have) Hurtig onboarding-skærm for nye spillere
+
+## PO-beslutninger (2026-02-27)
+- MVP: Første spil (Fup og Fakta) skal være spilbart end-to-end og stabilt.
+- Realtime: WebSocket er krav i MVP (ingen polling).
+- Join: kun i LOBBY i MVP (viewers senere).
+- Sikkerhed: sanitised inputs + server-side validering + fairness logging er hard requirement.
+- Spillere: default max 5, minimum 3 for start (konfigurerbart).
+- Se detaljer: coordination/PO_DECISIONS_2026-02-27.md.

coordination/PO_DECISIONS_2026-02-27.md

@@ -0,0 +1,41 @@
+# PO decisions — 2026-02-27
+
+## MVP scope
+- MVP = første spil (`Fup og Fakta`) er spilbart end-to-end og fungerer stabilt.
+- Platformen skal fra start være modulariseret så flere spil kan tilføjes senere.
+
+## Realtime
+- WebSocket er et krav i MVP (ikke polling).
+- Redis/RabbitMQ er muligt senere for skalering; Redis kan bruges tidligt til channels layer.
+
+## Join-regel
+- Spillere kan kun joine i `LOBBY` i MVP.
+- Viewers/observers er post-MVP.
+
+## Sikkerhed / "anti-cheat"
+- Fokus i MVP: sikre/sanitized user inputs og robust server-side validering.
+- Hard requirements i første spilbare version:
+  - input sanitation (XSS/angrebsvektorer)
+  - server-side validering af submit/guess-flow
+  - fairness logging
+
+## Release-klar kriterier
+1. Stabilitet er prioritet #1.
+2. Spillerantal er konfigurerbart; default: max 5, minimum 3 for at starte.
+3. Spilstruktur skal understøtte parametre:
+   - X = spørgsmål i kategori (stor pool)
+   - K = antal spørgsmål udvalgt pr. kategori (K < X)
+   - Z = antal kategorier i pool (stor pool)
+   - N = antal runder pr. spil
+   - M = antal kategorier pr. runde
+   - K og M holdes ens på tværs af runder i MVP
+
+## Eksempel
+- 4 runder, 3 kategorier pr. runde, 2 spørgsmål pr. kategori.
+
+## Prioriteret roadmap
+- M1: Lås MVP-scope + acceptkriterier
+- M2: End-to-end round engine
+- M3: Anti-cheat/sikkerhed enforcement + fairness logging
+- M4: Stabilitet/UX + release gates
+- M5: UI/high-performance forbedringer

coordination/assignments.json

@@ -1,5 +1,5 @@
 {
-  "updatedAt": "2026-02-27T12:00:57Z",
+  "updatedAt": "2026-02-27T13:38:35Z",
   "active": [],
   "queue": []
 }

docs/F0_ANTI_CHEAT_RULES.md

@@ -0,0 +1,53 @@
+# F0 anti-cheat regler — Fup og Fakta
+
+## Formål
+Fastlæg simple, håndhævelige anti-cheat regler for F0, så runderne opleves fair uden tung NLP/moderation.
+
+## Scope (F0)
+Gælder for inputfasen hvor spillere indsender løgne til et spørgsmål.
+
+## Regelsæt (F0)
+
+### 1) Ingen identiske løgne i samme runde
+- To spillere må ikke have samme løgntekst efter normalisering.
+- Hvis en indsendt løgn matcher en eksisterende løgn i runden, afvises den med fejlbesked og spilleren skal indsende ny tekst.
+
+### 2) Ingen løgn må være identisk med korrekt svar
+- En løgn, der matcher det korrekte svar efter normalisering, afvises.
+
+### 3) Ingen tomme eller trivielt ugyldige svar
+- Tom tekst, kun whitespace eller kun tegnsætning afvises.
+- Minimumslængde: 2 tegn efter trim.
+
+### 4) Én aktiv løgn pr. spiller pr. spørgsmål
+- Spilleren må gerne overskrive sin egen løgn inden deadline.
+- Ved deadline er kun seneste gyldige version gældende.
+
+### 5) Ingen afslørende metatekst
+- Svar som eksplicit afslører bluff-mekanikken (fx “det rigtige svar er …”, “jeg lyver”) afvises i F0 via enkel nøgleordsblokliste.
+
+## Normalisering (bruges i regel 1 + 2)
+Følgende normalisering anvendes før sammenligning:
+1. Unicode NFKC
+2. Trim + collapse af flere mellemrum til ét
+3. Lowercase
+4. Fjern afsluttende tegnsætning (`.`, `,`, `!`, `?`, `:` `;`)
+
+Bemærk: F0 bruger **ikke** semantisk duplikatdetektion (synonymer/stavevarianter kan passere).
+
+## Håndhævelse i UX/API
+- Validering sker server-side ved submit.
+- Klienten får konkret fejlårsag og kan indsende igen inden tidsfrist.
+- Samme valideringsregler gælder for alle klienter (web/mobil).
+
+## Acceptance criteria (F0)
+- Identiske løgne (efter normalisering) kan ikke gemmes i samme runde.
+- Løgn == korrekt svar (efter normalisering) kan ikke gemmes.
+- Tom/ugyldig input afvises.
+- Overskrivning af egen løgn inden deadline virker.
+- Ved deadline bruges kun seneste gyldige løgn.
+
+## Out-of-scope (bevidst udskudt)
+- Semantisk duplikatdetektion (embeddings/fuzzy matching)
+- Avanceret toxicitet/moderation
+- Sprogdetektion og translitterering

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-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/RELEASE_POLICY.md

@@ -0,0 +1,28 @@
+# Release policy (Issue #23)
+
+## Formål
+Sikre at release-tags altid repræsenterer faktisk deployet software.
+
+## Hård regel
+- **Ingen release-tag før staging deploy er succesfuld.**
+- **Ingen release-tag uden changelog-reference.**
+- **Ingen deploy hvis tester er i gang med smoke-run.**
+
+## Release-flow
+1. Bekræft architect-gate (`issue #17`) er release-approved.
+2. Bekræft tester ikke er aktiv.
+3. Deploy kandidat til staging (`infra/staging/deploy_staging.sh`).
+4. Verificér `/healthz` + smoke-resultat.
+5. Tilføj changelog-entry i `CHANGELOG.md`.
+6. Opret release-tag i Gitea (annotated), og referér changelog-sektion i release-notes.
+
+## Minimum release-notes template
+```markdown
+## Changelog
+- Ref: CHANGELOG.md#<sektion>
+
+## Deploy
+- Environment: staging
+- Status: success
+- Healthz: ok
+```

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

@@ -0,0 +1,48 @@
+# UI smoke (MVP)
+
+## Forudsætning
+- 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. 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/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/spa-cutover-flag.md

@@ -0,0 +1,74 @@
+# 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.
+
+## 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 +1,247 @@
+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' }]
+          },
+          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: true,
+              can_mix_answers: true,
+              can_calculate_scores: true,
+              can_reveal_scoreboard: true,
+              can_start_next_round: true,
+              can_finish_game: true
+            },
+            player: {
+              can_join: true,
+              can_submit_lie: true,
+              can_submit_guess: true,
+              can_view_final_result: false
+            }
+          }
+        } as T;
+      }
+
+      if (url === '/lobby/sessions/ABCD12/scoreboard') {
+        return {
+          session: { code: 'ABCD12', status: 'reveal', 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,
+          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(true);
+      expect(session.data.phase_view_model.player.can_submit_guess).toBe(true);
+    }
+
+    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 +1,266 @@
+import { afterEach, describe, expect, it, vi } from 'vitest';
+
+import { HostShellComponent } from './host-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?: { roundQuestionId?: number | 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 },
+    ],
+    phase_view_model: {
+      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,
+      },
+      host: {
+        can_start_round: status === 'lobby',
+        can_show_question: status === 'lie',
+        can_mix_answers: status === 'lie',
+        can_calculate_scores: status === 'guess',
+        can_reveal_scoreboard: status === 'reveal',
+        can_start_next_round: status === 'scoreboard',
+        can_finish_game: 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('captures scoreboard error for retry path', async () => {
+    const fetchMock: FetchMock = vi.fn().mockResolvedValue(jsonResponse(500, { error: 'Scoreboard unavailable' }));
+
+    vi.stubGlobal('fetch', fetchMock);
+
+    const component = new HostShellComponent();
+    component.sessionCode = 'ABCD12';
+
+    await component.loadScoreboard();
+
+    expect(fetchMock).toHaveBeenCalledWith('/lobby/sessions/ABCD12/scoreboard', expect.objectContaining({ method: 'GET' }));
+    expect(component.scoreboardError).toContain('Scoreboard failed: Scoreboard unavailable');
+    expect(component.loading).toBe(false);
+  });
+
+  it('wires showQuestion, mixAnswers and calculateScores with expected request payloads', async () => {
+    const fetchMock: FetchMock = vi
+      .fn()
+      .mockResolvedValueOnce(
+        jsonResponse(200, {
+          round_question: {
+            id: 77,
+            round_number: 1,
+            prompt: 'Q?',
+            shown_at: '2026-01-01T00:00:00Z',
+            lie_deadline_at: '2026-01-01T00:00:45Z',
+          },
+          config: { lie_seconds: 45 },
+        })
+      )
+      .mockResolvedValueOnce(jsonResponse(200, sessionDetailPayload('lie', { roundQuestionId: 77 })))
+      .mockResolvedValueOnce(
+        jsonResponse(200, {
+          session: { code: 'ABCD12', status: 'guess', current_round: 1 },
+          round_question: { id: 77, round_number: 1 },
+          answers: [{ text: 'A' }],
+        })
+      )
+      .mockResolvedValueOnce(jsonResponse(200, sessionDetailPayload('guess', { roundQuestionId: 77 })))
+      .mockResolvedValueOnce(
+        jsonResponse(200, {
+          session: { code: 'ABCD12', status: 'reveal', current_round: 1 },
+          round_question: { id: 77, round_number: 1 },
+          events_created: 2,
+          leaderboard: [{ id: 1, nickname: 'Luna', score: 320 }],
+        })
+      )
+      .mockResolvedValueOnce(jsonResponse(200, sessionDetailPayload('reveal', { roundQuestionId: 77 })));
+
+    vi.stubGlobal('fetch', fetchMock);
+
+    const component = new HostShellComponent();
+    component.sessionCode = ' abcd12 ';
+    component.roundQuestionId = ' 77 ';
+
+    await component.showQuestion();
+    await component.mixAnswers();
+    await component.calculateScores();
+
+    expect(component.error).toBe('');
+    expect(component.loading).toBe(false);
+  });
+
+  it('runs next-round transition without reload and clears scoreboard payload', async () => {
+    const fetchMock: FetchMock = vi
+      .fn()
+      .mockResolvedValueOnce(jsonResponse(200, { session: { code: 'ABCD12', status: 'lobby', current_round: 2 } }))
+      .mockResolvedValueOnce(jsonResponse(200, sessionDetailPayload('lobby', { roundQuestionId: null })));
+
+    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 }];
+
+    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('lobby');
+    expect(component.scoreboardPayload).toBe('');
+    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';
+
+    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 = '   ';
+
+    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('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');
+  });
+});

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

@@ -0,0 +1,316 @@
+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 } from '../../../../../src/api/types';
+import { createVerticalSliceController } from '../../../../../src/spa/vertical-slice';
+import { clientHasNoAudioOutput, resolvePreferredLocale, subscribeToLocaleChanges, t } from '../../lobby-i18n';
+
+interface SessionDetail {
+  session: { code: string; status: string; current_round: number };
+  round_question: { id: number; prompt: string; answers: Array<{ text: string }> } | null;
+  players: Array<{ id: number; nickname: string; score: number }>;
+}
+
+type LeaderboardEntry = ScoreboardResponse['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>{{ copy('host.category') }} <input [(ngModel)]="categorySlug" /></label>
+      <button (click)="refreshSession()" [disabled]="loading">{{ copy('common.refresh') }}</button>
+      <button (click)="startRound()" [disabled]="loading">{{ copy('host.start_round') }}</button>
+      <button (click)="showQuestion()" [disabled]="loading || !roundQuestionId">{{ copy('host.show_question') }}</button>
+      <button (click)="mixAnswers()" [disabled]="loading || !roundQuestionId">{{ copy('host.mix_answers') }}</button>
+      <button (click)="calculateScores()" [disabled]="loading || !roundQuestionId">{{ copy('host.calculate_scores') }}</button>
+      <button (click)="loadScoreboard()" [disabled]="loading">{{ copy('host.load_scoreboard') }}</button>
+      <button (click)="startNextRound()" [disabled]="loading">{{ copy('host.start_next_round') }}</button>
+      <button (click)="finishGame()" [disabled]="loading">{{ copy('host.finish_game') }}</button>
+      <button *ngIf="scoreboardError" (click)="loadScoreboard()" [disabled]="loading">{{ copy('host.retry_scoreboard') }}</button>
+      <button *ngIf="nextRoundError" (click)="startNextRound()" [disabled]="loading">{{ copy('host.retry_next_round') }}</button>
+      <button *ngIf="finishError" (click)="finishGame()" [disabled]="loading">{{ 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="scoreboardError" class="error">{{ scoreboardError }}</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>
+      <pre *ngIf="scoreboardPayload">{{ scoreboardPayload }}</pre>
+      <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;
+  }
+
+  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')}: ${(error as Error).message}`;
+    } finally {
+      this.loading = false;
+    }
+  }
+
+  async startRound(): Promise<void> {
+    await this.runAction(async () => {
+      const state = await this.controller.startRound(this.sessionCode, this.categorySlug.trim());
+      if (!state.session || state.errorMessage) {
+        throw new Error(state.errorMessage ?? this.copy('common.unknown_error'));
+      }
+      this.session = state.session as SessionDetail;
+      this.sessionCode = this.session.session.code;
+      this.persistSessionCode(this.sessionCode);
+      this.roundQuestionId = this.session.round_question?.id ? String(this.session.round_question.id) : '';
+      this.scoreboardPayload = '';
+      this.resetFinalLeaderboard();
+      this.syncRouteFromSession();
+    });
+  }
+
+  async showQuestion(): Promise<void> {
+    await this.runAction(async () => {
+      const code = this.normalizeCode(this.sessionCode);
+      await this.request(`/lobby/sessions/${encodeURIComponent(code)}/questions/show`, 'POST', {});
+      await this.refreshSession();
+    });
+  }
+
+  async mixAnswers(): Promise<void> {
+    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> {
+    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> {
+    this.loading = true;
+    this.scoreboardError = '';
+    this.error = '';
+    try {
+      const code = this.normalizeCode(this.sessionCode);
+      const payload = await this.request<unknown>(`/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')}: ${(error as Error).message}`;
+    } finally {
+      this.loading = false;
+    }
+  }
+
+  async startNextRound(): Promise<void> {
+    this.loading = true;
+    this.nextRoundError = '';
+    this.error = '';
+    try {
+      const code = this.normalizeCode(this.sessionCode);
+      if (!code) {
+        throw new Error(this.copy('host.session_code_required'));
+      }
+      await this.request(`/lobby/sessions/${encodeURIComponent(code)}/rounds/next`, 'POST', {});
+      this.scoreboardPayload = '';
+      this.resetFinalLeaderboard();
+      await this.refreshSession();
+    } catch (error) {
+      this.nextRoundError = `${this.copy('host.next_round_failed')}: ${(error as Error).message}`;
+    } finally {
+      this.loading = false;
+    }
+  }
+
+  async finishGame(): Promise<void> {
+    this.loading = true;
+    this.finishError = '';
+    this.error = '';
+    try {
+      const code = this.normalizeCode(this.sessionCode);
+      if (!code) {
+        throw new Error(this.copy('host.session_code_required'));
+      }
+      const payload = await this.request<LeaderboardResponse>(`/lobby/sessions/${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')}: ${(error as Error).message}`;
+    } finally {
+      this.loading = false;
+    }
+  }
+
+  private resetFinalLeaderboard(): void {
+    this.finalLeaderboardPayload = '';
+    this.finalLeaderboard = [];
+    this.finalWinner = null;
+  }
+
+  private syncRouteFromSession(): void {
+    if (!this.session) {
+      return;
+    }
+
+    const phase = this.session.session.status || 'lobby';
+    const code = this.normalizeCode(this.session.session.code || this.sessionCode);
+    if (!code) {
+      return;
+    }
+
+    const targetPath = `#/host/${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 +1,521 @@
+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?: { answers?: string[]; players?: Array<{ id: number; nickname: string; score: number }>; roundQuestionId?: number | 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,
+    })),
+    phase_view_model: {
+      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,
+      },
+      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: status === 'lobby',
+        can_submit_lie: status === 'lie',
+        can_submit_guess: status === 'guess',
+        can_view_final_result: 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 = {
+      session: { code: 'ABCD12', status: 'lie', current_round: 1 },
+      round_question: { id: 11, prompt: 'Q?', answers: [] },
+      players: [],
+    };
+
+    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('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 = {
+      session: { code: 'ABCD12', status: 'guess', current_round: 1 },
+      round_question: { id: 11, prompt: 'Q?', answers: [{ text: 'A' }, { text: 'B' }] },
+      players: [],
+    };
+
+    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('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('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);
+  });
+
+});

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

@@ -0,0 +1,557 @@
+import { CommonModule } from '@angular/common';
+import { Component, OnDestroy, OnInit } from '@angular/core';
+import { FormsModule } from '@angular/forms';
+
+import { createApiClient } from '../../../../../src/api/client';
+import { createSessionContextStore } from '../../../../../src/spa/session-context-store';
+import { createVerticalSliceController } from '../../../../../src/spa/vertical-slice';
+import { clientHasNoAudioOutput, resolvePreferredLocale, subscribeToLocaleChanges, t } from '../../lobby-i18n';
+
+interface SessionDetail {
+  session: { code: string; status: string; current_round: number };
+  round_question: { id: number; prompt: string; answers: Array<{ text: string }> } | null;
+  players: Array<{ id: number; nickname: string; score: number }>;
+}
+
+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>{{ copy('player.nickname') }} <input [(ngModel)]="nickname" /></label>
+      <button (click)="refreshSession()" [disabled]="loading">{{ copy('common.refresh') }}</button>
+      <button (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>
+
+      <label>{{ copy('player.lie_label') }} <input [(ngModel)]="lieText" [disabled]="loading || session.session.status !== 'lie'" /></label>
+      <button (click)="submitLie()" [disabled]="loading || session.session.status !== 'lie'">{{ copy('player.submit_lie') }}</button>
+      <button *ngIf="submitError?.kind === 'lie'" (click)="submitLie()" [disabled]="loading">{{ copy('player.retry_lie_submit') }}</button>
+
+      <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 || session.session.status !== 'guess'"
+        >
+          {{ answer.text }}
+        </button>
+      </div>
+
+      <button (click)="submitGuess()" [disabled]="loading || session.session.status !== 'guess' || !selectedGuess">{{ copy('player.submit_guess') }}</button>
+      <button *ngIf="submitError?.kind === 'guess'" (click)="submitGuess()" [disabled]="loading">{{ copy('player.retry_guess_submit') }}</button>
+
+      <div *ngIf="session.session.status === 'finished' && 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;
+  }
+
+  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<GuardableMediaElement>
+      | 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 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.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')}: ${this.toMessage(error)}`;
+      this.markConnectionIssue(error);
+    } finally {
+      this.loading = false;
+      this.loadingTransition = null;
+    }
+  }
+
+  async submitLie(): Promise<void> {
+    if (!this.session?.round_question?.id) {
+      return;
+    }
+    this.loading = true;
+    this.loadingTransition = 'submit-lie';
+    this.submitError = null;
+    try {
+      await this.request(
+        `/lobby/sessions/${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')}: ${this.toMessage(error)}` };
+      this.markConnectionIssue(error);
+    } finally {
+      this.loading = false;
+      this.loadingTransition = null;
+    }
+  }
+
+  async submitGuess(): Promise<void> {
+    if (!this.session?.round_question?.id || !this.selectedGuess) {
+      return;
+    }
+    this.loading = true;
+    this.loadingTransition = 'submit-guess';
+    this.submitError = null;
+    try {
+      await this.request(
+        `/lobby/sessions/${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 +1,73 @@
+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';
+
+describe('i18n MVP flow smoke (host/player + audio policy)', () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+    vi.unstubAllGlobals();
+  });
+
+  it('resolves host/player copy in en and da from shared catalog', () => {
+    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(),
+    });
+    vi.stubGlobal('navigator', { language: 'en-US', onLine: true });
+
+    const host = new HostShellComponent();
+    const player = new PlayerShellComponent();
+    host.ngOnInit();
+    player.ngOnInit();
+
+    expect(host.copy('game.host.start_round')).toBe('Start round');
+    expect(player.copy('game.player.submit_guess')).toBe('Submit guess');
+
+    setPreferredLocale('da');
+
+    expect(host.copy('game.host.start_round')).toBe('Start runde');
+    expect(player.copy('game.player.submit_guess')).toBe('Send gæt');
+
+    player.ngOnDestroy();
+    host.ngOnDestroy();
+  });
+
+  it('keeps audio routing policy primary-only (client has no audio output)', 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() },
+      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('original play');
+
+    const player = new PlayerShellComponent();
+    player.ngOnInit();
+
+    await expect(mediaPrototype.play()).resolves.toBeUndefined();
+
+    player.ngOnDestroy();
+
+    await expect(mediaPrototype.play()).rejects.toThrow('original play');
+
+    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 +1,15 @@
+{
+  "name": "wpp-frontend-api-client-baseline",
+  "private": true,
+  "version": "0.1.0",
+  "type": "module",
+  "scripts": {
+    "test": "vitest run",
+    "build": "tsc --noEmit"
+  },
+  "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,
+  mapNextRoundResponse,
+  mapScoreboardResponse,
+  mapSessionDetailResponse,
+  mapShowQuestionResponse,
+  mapStartRoundResponse,
+  mapSubmitGuessResponse,
+  mapSubmitLieResponse
+} from './mappers';
+import type {
+  ApiResult,
+  CalculateScoresResponse,
+  FinishGameResponse,
+  HealthResponse,
+  JoinSessionRequest,
+  JoinSessionResponse,
+  MixAnswersResponse,
+  NextRoundResponse,
+  ScoreboardResponse,
+  SessionDetailResponse,
+  ShowQuestionResponse,
+  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<NextRoundResponse>>;
+  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/${encodeURIComponent(normalizeCode(code))}/scoreboard`,
+        'GET',
+        mapScoreboardResponse
+      ),
+    startNextRound: (code: string) =>
+      request<NextRoundResponse>(
+        `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/rounds/next`,
+        'POST',
+        mapNextRoundResponse,
+        {}
+      ),
+    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 +1,414 @@
+import type {
+  CalculateScoresResponse,
+  FinishGameResponse,
+  HealthResponse,
+  JoinSessionResponse,
+  MixAnswersResponse,
+  RevealPayload,
+  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;
+}
+
+export function mapHealthResponse(payload: unknown): HealthResponse {
+  const root = asRecord(payload, 'health');
+  return {
+    ok: readBoolean(root, 'ok', 'health'),
+    service: readString(root, 'service', 'health')
+  };
+}
+
+function mapRevealPayload(payload: unknown, path: string): RevealPayload {
+  const reveal = asRecord(payload, path);
+  const liesRaw = reveal.lies;
+  const guessesRaw = reveal.guesses;
+
+  if (!Array.isArray(liesRaw)) {
+    throw new Error(`Invalid API contract: expected array at ${path}.lies`);
+  }
+  if (!Array.isArray(guessesRaw)) {
+    throw new Error(`Invalid API contract: expected array at ${path}.guesses`);
+  }
+
+  return {
+    round_question_id: readNumber(reveal, 'round_question_id', path),
+    round_number: readNumber(reveal, 'round_number', path),
+    prompt: readString(reveal, 'prompt', path),
+    correct_answer: readString(reveal, 'correct_answer', path),
+    lies: liesRaw.map((lie, index) => {
+      const liePath = `${path}.lies[${index}]`;
+      const record = asRecord(lie, liePath);
+      return {
+        player_id: readNumber(record, 'player_id', liePath),
+        nickname: readString(record, 'nickname', liePath),
+        text: readString(record, 'text', liePath),
+        created_at: readString(record, 'created_at', liePath)
+      };
+    }),
+    guesses: guessesRaw.map((guess, index) => {
+      const guessPath = `${path}.guesses[${index}]`;
+      const record = asRecord(guess, guessPath);
+      const fooledPlayerId = record.fooled_player_id;
+      if (fooledPlayerId !== null && !isNumber(fooledPlayerId)) {
+        throw new Error(`Invalid API contract: expected number|null at ${guessPath}.fooled_player_id`);
+      }
+      const fooledPlayerNickname = record.fooled_player_nickname;
+      if (fooledPlayerNickname !== undefined && !isString(fooledPlayerNickname)) {
+        throw new Error(`Invalid API contract: expected string|undefined at ${guessPath}.fooled_player_nickname`);
+      }
+      return {
+        player_id: readNumber(record, 'player_id', guessPath),
+        nickname: readString(record, 'nickname', guessPath),
+        selected_text: readString(record, 'selected_text', guessPath),
+        is_correct: readBoolean(record, 'is_correct', guessPath),
+        created_at: readString(record, 'created_at', guessPath),
+        fooled_player_id: fooledPlayerId,
+        ...(fooledPlayerNickname === undefined ? {} : { fooled_player_nickname: fooledPlayerNickname })
+      };
+    })
+  };
+}
+
+function mapSessionDetail(payload: unknown): SessionDetailResponse {
+  const root = asRecord(payload, 'session_detail');
+  const session = asRecord(root.session, 'session_detail.session');
+  const players = root.players;
+  if (!Array.isArray(players)) {
+    throw new Error('Invalid API contract: expected array at session_detail.players');
+  }
+
+  const roundQuestionRaw = root.round_question;
+  let roundQuestion: SessionDetailResponse['round_question'] = null;
+  if (roundQuestionRaw !== null) {
+    const roundQuestionRecord = asRecord(roundQuestionRaw, 'session_detail.round_question');
+    const answersRaw = roundQuestionRecord.answers;
+    if (!Array.isArray(answersRaw)) {
+      throw new Error('Invalid API contract: expected array at session_detail.round_question.answers');
+    }
+
+    roundQuestion = {
+      id: readNumber(roundQuestionRecord, 'id', 'session_detail.round_question'),
+      round_number: readNumber(roundQuestionRecord, 'round_number', 'session_detail.round_question'),
+      prompt: readString(roundQuestionRecord, 'prompt', 'session_detail.round_question'),
+      shown_at: readString(roundQuestionRecord, 'shown_at', 'session_detail.round_question'),
+      answers: answersRaw.map((answer, index) => {
+        const answerRecord = asRecord(answer, `session_detail.round_question.answers[${index}]`);
+        return { text: readString(answerRecord, 'text', `session_detail.round_question.answers[${index}]`) };
+      })
+    };
+  }
+
+  const revealRaw = root.reveal;
+  const phase = asRecord(root.phase_view_model, 'session_detail.phase_view_model');
+  const constraints = asRecord(phase.constraints, 'session_detail.phase_view_model.constraints');
+  const host = asRecord(phase.host, 'session_detail.phase_view_model.host');
+  const player = asRecord(phase.player, 'session_detail.phase_view_model.player');
+
+  return {
+    session: {
+      code: readString(session, 'code', 'session_detail.session'),
+      status: readString(session, 'status', 'session_detail.session'),
+      host_id: (() => {
+        const hostId = session.host_id;
+        if (hostId === null) {
+          return null;
+        }
+        if (!isNumber(hostId)) {
+          throw new Error('Invalid API contract: expected number|null at session_detail.session.host_id');
+        }
+        return hostId;
+      })(),
+      current_round: readNumber(session, 'current_round', 'session_detail.session'),
+      players_count: readNumber(session, 'players_count', 'session_detail.session')
+    },
+    players: players.map((item, index) => {
+      const record = asRecord(item, `session_detail.players[${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: revealRaw === null || revealRaw === undefined ? null : mapRevealPayload(revealRaw, 'session_detail.reveal'),
+    phase_view_model: {
+      status: readString(phase, 'status', 'session_detail.phase_view_model'),
+      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')
+      },
+      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'),
+    reveal: mapRevealPayload(root.reveal, 'calculate_scores.reveal'),
+    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 = guess.fooled_player_id;
+  if (fooledPlayerId !== null && !isNumber(fooledPlayerId)) {
+    throw new Error('Invalid API contract: expected number|null at submit_guess.guess.fooled_player_id');
+  }
+
+  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 +1,251 @@
+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;
+  round_number: number;
+  players_count: number;
+  constraints: {
+    min_players_to_start: number;
+    max_players_mvp: number;
+    min_players_reached: boolean;
+    max_players_allowed: 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 RevealPlayerRef {
+  player_id: number;
+  nickname: string;
+}
+
+export interface RevealLie extends RevealPlayerRef {
+  text: string;
+  created_at: string;
+}
+
+export interface RevealGuess extends RevealPlayerRef {
+  selected_text: string;
+  is_correct: boolean;
+  created_at: string;
+  fooled_player_id: number | null;
+  fooled_player_nickname?: 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;
+  reveal: RevealPayload;
+  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 +1,58 @@
+import type { SessionDetailResponse } from '../api/types';
+
+export type GameplayPhase = 'lie' | 'guess' | 'reveal' | 'scoreboard';
+
+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[];
+}
+
+export function deriveGameplayPhase(session: SessionDetailResponse | null): GameplayPhase | null {
+  const status = session?.session.status;
+  if (!status) {
+    return null;
+  }
+
+  if (status === 'lie' || status === 'guess' || status === 'reveal' || status === 'scoreboard') {
+    return status;
+  }
+
+  if (status === 'finished') {
+    return 'scoreboard';
+  }
+
+  return null;
+}

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 +1,528 @@
+import { describe, expect, it, vi } from 'vitest';
+
+import { createAngularApiClient, type AngularHttpClientLike } from '../src/api/angular-client';
+
+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,
+          reveal: 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.reveal).toBeNull();
+      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,
+          reveal: 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('maps canonical reveal payload from session detail in reveal phase', 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: 3 },
+          players: [
+            { id: 2, nickname: 'Maja', score: 4, is_connected: true },
+            { id: 3, nickname: 'Bo', score: 2, is_connected: true },
+            { id: 4, nickname: 'Ida', score: 5, is_connected: true }
+          ],
+          round_question: {
+            id: 77,
+            round_number: 1,
+            prompt: 'Hvem opfandt pæren?',
+            shown_at: '2026-03-01T16:00:00Z',
+            answers: [{ text: 'Edison' }, { text: 'Tesla' }]
+          },
+          reveal: {
+            round_question_id: 77,
+            round_number: 1,
+            prompt: 'Hvem opfandt pæren?',
+            correct_answer: 'Edison',
+            lies: [
+              {
+                player_id: 3,
+                nickname: 'Bo',
+                text: 'Tesla',
+                created_at: '2026-03-01T16:00:20Z'
+              }
+            ],
+            guesses: [
+              {
+                player_id: 2,
+                nickname: 'Maja',
+                selected_text: 'Tesla',
+                is_correct: false,
+                fooled_player_id: 3,
+                fooled_player_nickname: 'Bo',
+                created_at: '2026-03-01T16:01:00Z'
+              },
+              {
+                player_id: 4,
+                nickname: 'Ida',
+                selected_text: 'Edison',
+                is_correct: true,
+                fooled_player_id: null,
+                created_at: '2026-03-01T16:01:02Z'
+              }
+            ]
+          },
+          phase_view_model: {
+            status: 'reveal',
+            round_number: 1,
+            players_count: 3,
+            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: true,
+              can_finish_game: true
+            },
+            player: {
+              can_join: false,
+              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 AngularHttpClientLike);
+    const session = await client.getSession('abcd12');
+
+    expect(session.ok).toBe(true);
+    if (session.ok) {
+      expect(session.data.reveal?.correct_answer).toBe('Edison');
+      expect(session.data.reveal?.lies[0]).toMatchObject({
+        player_id: 3,
+        nickname: 'Bo',
+        text: 'Tesla'
+      });
+      expect(session.data.reveal?.guesses[0]).toMatchObject({
+        player_id: 2,
+        nickname: 'Maja',
+        selected_text: 'Tesla',
+        is_correct: false,
+        fooled_player_id: 3,
+        fooled_player_nickname: 'Bo'
+      });
+      expect(session.data.reveal?.guesses[1]).toMatchObject({
+        player_id: 4,
+        nickname: 'Ida',
+        selected_text: 'Edison',
+        is_correct: true,
+        fooled_player_id: null
+      });
+    }
+  });
+
+  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('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: 'reveal', 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: 'reveal', current_round: 1 },
+          round_question: { id: 77, round_number: 1 },
+          events_created: 3,
+          reveal: {
+            round_question_id: 77,
+            round_number: 1,
+            prompt: 'Hvem opfandt pæren?',
+            correct_answer: 'Edison',
+            lies: [
+              {
+                player_id: 3,
+                nickname: 'Bo',
+                text: 'Tesla',
+                created_at: '2026-03-01T16:00:20Z'
+              }
+            ],
+            guesses: [
+              {
+                player_id: 2,
+                nickname: 'Maja',
+                selected_text: 'Tesla',
+                is_correct: false,
+                fooled_player_id: 3,
+                fooled_player_nickname: 'Bo',
+                created_at: '2026-03-01T16:01:00Z'
+              },
+              {
+                player_id: 4,
+                nickname: 'Ida',
+                selected_text: 'Edison',
+                is_correct: true,
+                fooled_player_id: null,
+                created_at: '2026-03-01T16:01:02Z'
+              }
+            ]
+          },
+          leaderboard: [{ id: 2, nickname: 'Maja', score: 11 }]
+        } as T;
+      }
+      if (url === '/lobby/sessions/ABCD12/rounds/next') {
+        expect(body).toEqual({});
+        return { session: { code: 'ABCD12', status: 'lobby', 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);
+    if (calculateScores.ok) {
+      expect(calculateScores.data.reveal.correct_answer).toBe('Edison');
+      expect(calculateScores.data.reveal.lies[0]).toMatchObject({
+        player_id: 3,
+        nickname: 'Bo',
+        text: 'Tesla'
+      });
+      expect(calculateScores.data.reveal.guesses[0]).toMatchObject({
+        player_id: 2,
+        nickname: 'Maja',
+        selected_text: 'Tesla',
+        is_correct: false,
+        fooled_player_id: 3,
+        fooled_player_nickname: 'Bo'
+      });
+      expect(calculateScores.data.reveal.guesses[1]).toMatchObject({
+        player_id: 4,
+        nickname: 'Ida',
+        selected_text: 'Edison',
+        is_correct: true,
+        fooled_player_id: null
+      });
+    }
+
+    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 +1,106 @@
+import { describe, expect, it } from 'vitest';
+import {
+  allowedGameplayEvents,
+  deriveGameplayPhase,
+  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,
+        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,
+        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');
+  });
+});

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 +1,227 @@
+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,
+        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' } }
+      }
+    })
+  };
+
+  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 +1,8 @@
+import { defineConfig } from 'vitest/config';
+
+export default defineConfig({
+  test: {
+    include: ['tests/**/*.test.ts'],
+    exclude: ['**/node_modules/**']
+  }
+});

fupogfakta/migrations/0002_roundquestion_shown_at.py

@@ -0,0 +1,19 @@
+# Generated by Django 6.0.2 on 2026-02-27 13:32
+
+import django.utils.timezone
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("fupogfakta", "0001_initial"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="roundquestion",
+            name="shown_at",
+            field=models.DateTimeField(default=django.utils.timezone.now),
+        ),
+    ]

fupogfakta/migrations/0003_roundquestion_mixed_answers.py

@@ -0,0 +1,18 @@
+# Generated by Django 6.0.2 on 2026-02-27 21:57
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('fupogfakta', '0002_roundquestion_shown_at'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='roundquestion',
+            name='mixed_answers',
+            field=models.JSONField(blank=True, default=list),
+        ),
+    ]

fupogfakta/migrations/0004_player_session_token.py

@@ -0,0 +1,19 @@
+# Generated by Django 6.0.2 on 2026-02-27 22:08
+
+import fupogfakta.models
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('fupogfakta', '0003_roundquestion_mixed_answers'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='player',
+            name='session_token',
+            field=models.CharField(db_index=True, default=fupogfakta.models._generate_player_session_token, max_length=64),
+        ),
+    ]

fupogfakta/models.py

@@ -1,8 +1,15 @@
+import secrets
+
 from django.db import models
 from django.contrib.auth import get_user_model
+from django.utils import timezone
 
 User = get_user_model()
 
+def _generate_player_session_token() -> str:
+    return secrets.token_urlsafe(24)
+
+
 
 class Category(models.Model):
     name = models.CharField(max_length=120, unique=True)
@@ -53,6 +60,7 @@ class GameSession(models.Model):
 class Player(models.Model):
     session = models.ForeignKey(GameSession, on_delete=models.CASCADE, related_name="players")
     nickname = models.CharField(max_length=40)
+    session_token = models.CharField(max_length=64, db_index=True, default=_generate_player_session_token)
     score = models.IntegerField(default=0)
     is_connected = models.BooleanField(default=True)
     created_at = models.DateTimeField(auto_now_add=True)
@@ -85,6 +93,8 @@ class RoundQuestion(models.Model):
     round_number = models.PositiveIntegerField()
     question = models.ForeignKey(Question, on_delete=models.PROTECT)
     correct_answer = models.CharField(max_length=255)
+    shown_at = models.DateTimeField(default=timezone.now)
+    mixed_answers = models.JSONField(default=list, blank=True)
 
 
 class LieAnswer(models.Model):

fupogfakta/tests.py

@@ -1,3 +1,2 @@
-from django.test import TestCase
 
 # Create your tests here.

fupogfakta/views.py

@@ -1,3 +1,2 @@
-from django.shortcuts import render
 
 # Create your views here.

infra/env/.env.staging.example

@@ -0,0 +1,12 @@
+DJANGO_SECRET_KEY=change-me-staging
+DJANGO_DEBUG=false
+DJANGO_ALLOWED_HOSTS=staging.party.weircon.dk
+DB_ENGINE=django.db.backends.mysql
+DB_NAME=wpp_staging
+DB_USER=wpp_staging
+DB_PASSWORD=change-me
+DB_HOST=127.0.0.1
+DB_PORT=3306
+TEST_DB_NAME=
+CHANNEL_REDIS_HOST=127.0.0.1
+CHANNEL_REDIS_PORT=6379