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.

web/src/index.css

@@ -0,0 +1,14 @@
+@tailwind base;
+@tailwind components;
+@tailwind utilities;
+
+html,
+body,
+#root {
+  height: 100%;
+}
+
+body {
+  margin: 0;
+  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
+}