Add web client and containerized deployment stack

Web client:

- Added React + TypeScript + Vite + Tailwind application in web/.

- Implemented auth, chat list, chat messages, typing indicators, file uploads, and voice recording/playback.

- Added typed API layer, Zustand stores, and realtime websocket hook integration.

Containerization:

- Added backend Dockerfile and project .dockerignore.

- Added web multi-stage Dockerfile with nginx static hosting and API/WS reverse proxy.

- Added full docker-compose stack with postgres, redis, minio, backend, worker, mailpit, and web.

- Added MinIO bucket bootstrap init job and updated README with Docker quick-start.

README.md

@@ -23,3 +23,21 @@ celery -A app.celery_app:celery_app worker --loglevel=info
   python -m compileall app main.py
 - Tests:
   pytest -q
+
+## Web Client
+
+1. cd web
+2. copy `.env.example` to `.env`
+3. npm install
+4. npm run dev
+
+## Docker Quick Start
+
+Run full stack (web + api + worker + postgres + redis + minio + mailpit):
+
+1. docker compose up --build
+2. Open:
+   - Web: http://localhost
+   - API docs: http://localhost:8000/docs
+   - Mailpit UI: http://localhost:8025
+   - MinIO console: http://localhost:9001