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/nginx.conf

@@ -0,0 +1,28 @@
+server {
+  listen 80;
+  server_name _;
+
+  root /usr/share/nginx/html;
+  index index.html;
+
+  location / {
+    try_files $uri $uri/ /index.html;
+  }
+
+  location /api/ {
+    proxy_pass http://backend:8000/api/;
+    proxy_http_version 1.1;
+    proxy_set_header Host $host;
+    proxy_set_header X-Forwarded-Proto $scheme;
+    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+  }
+
+  location /api/v1/realtime/ws {
+    proxy_pass http://backend:8000/api/v1/realtime/ws;
+    proxy_http_version 1.1;
+    proxy_set_header Upgrade $http_upgrade;
+    proxy_set_header Connection "upgrade";
+    proxy_set_header Host $host;
+    proxy_read_timeout 3600;
+  }
+}