test(08-01): add integration tests for chat window open/close

- Expose Redux store for testing (dev/test environments only)
- Add 3 tests: window open, window close, placeholder message
- Tests verify WindowPortal integration and Redux state updates

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

jam-ui/src/store/store.js

@@ -17,7 +17,7 @@ import mixersReducer from "./features/mixersSlice"
 import mediaReducer from "./features/mediaSlice"
 import sessionChatReducer from "./features/sessionChatSlice"
 
-export default configureStore({
+const store = configureStore({
   reducer: {
     textMessage: textMessageReducer,
     people: peopleReducer,
@@ -37,4 +37,11 @@ export default configureStore({
     myJamTrack: myJamTracksSlice,
     jamTrack: jamTrackSlice
   }
-})
+})
+
+// Expose store for testing (development and test environments only)
+if (process.env.NODE_ENV === 'development' || process.env.NODE_ENV === 'test') {
+  window.__REDUX_STORE__ = store;
+}
+
+export default store

jam-ui/test/chat/chat-window.spec.ts

@@ -0,0 +1,81 @@
+import { test, expect } from '@playwright/test';
+import { loginToJamUI, createAndJoinSession } from '../utils/test-helpers';
+
+test.describe('Chat Window', () => {
+  test.beforeEach(async ({ page }) => {
+    await loginToJamUI(page);
+    await createAndJoinSession(page);
+  });
+
+  test('opens chat window when dispatching openChatWindow action', async ({ page, context }) => {
+    // Dispatch openChatWindow action via Redux
+    await page.evaluate(() => {
+      const store = (window as any).__REDUX_STORE__;
+      if (!store) {
+        throw new Error('Redux store not exposed for testing');
+      }
+      store.dispatch({ type: 'sessionChat/openChatWindow' });
+    });
+
+    // Wait for popup window
+    const popupPromise = context.waitForEvent('page');
+    const popup = await popupPromise;
+
+    // Verify popup opened
+    expect(popup).toBeTruthy();
+    await expect(popup).toHaveTitle('JamKazam Chat');
+
+    // Verify header content
+    const header = popup.locator('h5');
+    await expect(header).toBeVisible();
+    await expect(header).toContainText('Chat');
+  });
+
+  test('closes chat window when clicking close button', async ({ page, context }) => {
+    // Open chat window
+    await page.evaluate(() => {
+      const store = (window as any).__REDUX_STORE__;
+      store.dispatch({ type: 'sessionChat/openChatWindow' });
+    });
+
+    const popupPromise = context.waitForEvent('page');
+    const popup = await popupPromise;
+
+    // Wait for popup to be ready
+    await popup.waitForLoadState('domcontentloaded');
+
+    // Click close button
+    const closeButton = popup.locator('button[aria-label="Close chat"]');
+    await expect(closeButton).toBeVisible();
+    await closeButton.click();
+
+    // Verify popup closed (wait a bit for close to complete)
+    await page.waitForTimeout(1000);
+    expect(popup.isClosed()).toBe(true);
+
+    // Verify Redux state updated
+    const isWindowOpen = await page.evaluate(() => {
+      const store = (window as any).__REDUX_STORE__;
+      return store.getState().sessionChat.isWindowOpen;
+    });
+    expect(isWindowOpen).toBe(false);
+  });
+
+  test('shows placeholder message before messages loaded', async ({ page, context }) => {
+    // Open chat window
+    await page.evaluate(() => {
+      const store = (window as any).__REDUX_STORE__;
+      store.dispatch({ type: 'sessionChat/openChatWindow' });
+    });
+
+    const popupPromise = context.waitForEvent('page');
+    const popup = await popupPromise;
+
+    // Wait for popup to be ready
+    await popup.waitForLoadState('domcontentloaded');
+
+    // Verify placeholder text
+    const placeholder = popup.locator('p:has-text("Chat messages will appear here")');
+    await expect(placeholder).toBeVisible();
+  });
+});