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/tailwind.config.ts

@@ -0,0 +1,16 @@
+import type { Config } from "tailwindcss";
+
+export default {
+  content: ["./index.html", "./src/**/*.{ts,tsx}"],
+  theme: {
+    extend: {
+      colors: {
+        bg: "#0f172a",
+        panel: "#111827",
+        accent: "#14b8a6",
+        text: "#e5e7eb"
+      }
+    }
+  },
+  plugins: []
+} satisfies Config;