Initial CloudLink scaffold: E2E encrypted PWA with messaging and cloud drive

- Zero-knowledge architecture: all encryption/decryption client-side via Web Crypto API
- AES-GCM 256 for messages, files, and key wrapping; PBKDF2 for password-based key derivation
- Node.js/TypeScript backend: JWT auth with refresh rotation, argon2id passwords, TOTP 2FA
- PostgreSQL schema: encrypted blobs only, server never stores plaintext
- Real-time messaging via WebSocket relay (server routes ciphertext, cannot read it)
- Encrypted file upload/download with per-file keys wrapped by user master key
- React PWA frontend: Vite + Tailwind + service worker for offline support
- Docker Compose: postgres + backend + frontend + nginx with TLS

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/Dockerfile

@@ -0,0 +1,15 @@
+FROM node:20-alpine AS builder
+WORKDIR /app
+COPY package*.json ./
+RUN npm ci
+COPY . .
+RUN npm run build
+
+FROM node:20-alpine
+WORKDIR /app
+COPY package*.json ./
+RUN npm ci --omit=dev
+COPY --from=builder /app/dist ./dist
+RUN mkdir -p /data/uploads
+EXPOSE 3001
+CMD ["node", "dist/index.js"]