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>

README.md

@@ -0,0 +1,52 @@
+# KeepItTalking
+
+A web-based team chat service (Mattermost-style, no threaded conversations),
+invite-only. See [ARCHITECTURE.md](ARCHITECTURE.md) for the full system design
+and phased build plan.
+
+**Phase 1** (this state of the repo): auth, open-room CRUD, and single-instance
+WebSocket chat, backend + a minimal frontend. Later phases (private rooms,
+push notifications, Redis fan-out, the admin portal, the bot/extension
+system, and production deployment) are tracked as issues in the repo's issue
+tracker, prioritized.
+
+## Structure
+
+- [`backend/`](backend/) — FastAPI + SQLAlchemy 2.0 (async) + PostgreSQL. See
+  [`backend/README.md`](backend/README.md) for local setup, migrations, and
+  how to create a user (registration is invite-only — there's no public
+  sign-up endpoint).
+- [`frontend/`](frontend/) — React + Vite PWA (login, room list, chat view).
+
+## Quickstart
+
+```bash
+# 1. Postgres (see backend/README.md for details)
+docker run -d --name chatapp-postgres \
+  -e POSTGRES_USER=chatapp -e POSTGRES_PASSWORD=chatapp -e POSTGRES_DB=chatapp \
+  -p 5432:5432 postgres:16-alpine
+
+# 2. Backend
+cd backend
+python3 -m venv .venv
+.venv/bin/pip install -e ".[dev]"
+cp .env.example .env   # then set SESSION_SECRET
+.venv/bin/alembic upgrade head
+.venv/bin/python -m app.cli create-user alice alice@example.com "some-password"
+.venv/bin/uvicorn app.main:app --reload &
+
+# 3. Frontend (in another shell)
+cd frontend
+npm install
+npm run dev
+```
+
+Then open http://localhost:5173 and log in with the account created above.
+The Vite dev server proxies `/api` and `/ws` to the backend on `:8000`, so no
+CORS configuration is needed in development.
+
+## Deployment
+
+Not part of Phase 1. The target is two plain Linux servers with no
+containers — see [ARCHITECTURE.md §9](ARCHITECTURE.md#9-deployment-architecture--two-linux-servers-no-docker)
+and the corresponding "Production deployment" issue in the tracker.