feat(frontend): wire SPA flow to session context store

frontend/tests/vertical-slice.test.ts

@@ -1,5 +1,6 @@
 import { describe, expect, it, vi } from 'vitest';
 import { createVerticalSliceController } from '../src/spa/vertical-slice';
+import { createSessionContextStore, type StorageLike } from '../src/spa/session-context-store';
 import type { ApiClient } from '../src/api/client';
 
 function makeApiMock(overrides?: Partial<ApiClient>): ApiClient {
@@ -58,10 +59,24 @@ function makeApiMock(overrides?: Partial<ApiClient>): ApiClient {
   return { ...base, ...overrides };
 }
 
+function makeMemoryStorage(): StorageLike {
+  const memory = new Map<string, string>();
+  return {
+    getItem: (key: string) => memory.get(key) ?? null,
+    setItem: (key: string, value: string) => {
+      memory.set(key, value);
+    },
+    removeItem: (key: string) => {
+      memory.delete(key);
+    }
+  };
+}
+
 describe('vertical slice controller: lobby -> join -> start round', () => {
-  it('tracks loading and success state for join + start flow', async () => {
+  it('tracks loading and success state for join + start flow and stores session context', async () => {
     const api = makeApiMock();
-    const controller = createVerticalSliceController(api);
+    const store = createSessionContextStore(makeMemoryStorage());
+    const controller = createVerticalSliceController(api, store);
 
     const beforeJoinPromise = controller.joinLobby('abcd12', 'Maja');
     expect(controller.getState().joinState).toBe('loading');
@@ -70,13 +85,15 @@ describe('vertical slice controller: lobby -> join -> start round', () => {
     const postJoin = controller.getState();
     expect(postJoin.joinState).toBe('success');
     expect(postJoin.session?.session.code).toBe('ABCD12');
+    expect(postJoin.context).toEqual({ sessionCode: 'ABCD12', playerId: 9, token: 'token-1' });
 
-    const beforeStartPromise = controller.startRound('abcd12', 'history');
+    const beforeStartPromise = controller.startRound('', 'history');
     expect(controller.getState().startRoundState).toBe('loading');
     await beforeStartPromise;
 
     const postStart = controller.getState();
     expect(postStart.startRoundState).toBe('success');
+    expect(api.startRound).toHaveBeenCalledWith('ABCD12', { category_slug: 'history' });
   });
 
   it('surfaces a friendly error when join fails', async () => {
@@ -112,4 +129,15 @@ describe('vertical slice controller: lobby -> join -> start round', () => {
     expect(state.startRoundState).toBe('error');
     expect(state.errorMessage).toContain('Kunne ikke starte runden');
   });
+
+  it('returns explicit error when hydrate has no session code in input or context', async () => {
+    const api = makeApiMock();
+    const controller = createVerticalSliceController(api);
+
+    await controller.hydrateLobby('   ');
+
+    const state = controller.getState();
+    expect(state.errorMessage).toContain('Session-kode mangler');
+    expect(api.getSession).not.toHaveBeenCalled();
+  });
 });