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/Dockerfile

@@ -0,0 +1,14 @@
+FROM node:20-alpine AS build
+
+WORKDIR /web
+COPY package.json package-lock.json* ./
+RUN npm install
+
+COPY . .
+RUN npm run build
+
+FROM nginx:1.27-alpine
+COPY nginx.conf /etc/nginx/conf.d/default.conf
+COPY --from=build /web/dist /usr/share/nginx/html
+
+EXPOSE 80