Phase 1: auth, room CRUD, WebSocket chat, PWA frontend

Invite-only FastAPI + SQLAlchemy(async) + Postgres backend (session-cookie
auth via CLI-provisioned accounts, open-room CRUD, single-instance /ws/chat)
and a React + Vite PWA frontend (login, room list, chat view). Backend tests
pass against a local Postgres DB. See README.md and backend/README.md for
setup, and ARCHITECTURE.md for the full phased design.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

frontend/README.md

@@ -0,0 +1,36 @@
+# KeepItTalking frontend (Phase 1)
+
+React + Vite PWA. Login, room list, and chat views wired to the backend's
+REST API and `/ws/chat` WebSocket endpoint. See [`../README.md`](../README.md)
+and [`../backend/README.md`](../backend/README.md) for full local setup.
+
+## Dev
+
+```bash
+npm install
+npm run dev
+```
+
+The dev server proxies `/api` and `/ws` to `http://localhost:8000` (see
+`vite.config.ts`), so the backend must be running for anything beyond the
+login page to work.
+
+## Build
+
+```bash
+npm run build
+```
+
+Generates the PWA manifest and service worker via `vite-plugin-pwa` into `dist/`.
+
+## Layout
+
+```
+src/
+  main.tsx, App.tsx        routes: /login, /rooms, /rooms/:roomId
+  api/                       fetch wrappers (client, auth, rooms)
+  ws/useChatSocket.ts          WebSocket hook (join/send/receive)
+  context/AuthContext.tsx        current-user state, hydrated via GET /api/auth/me
+  components/                      ProtectedRoute, RoomListItem, MessageList, MessageInput
+  pages/                             LoginPage, RoomListPage, ChatRoomPage
+```