1. Copy .env.example to .env and fill secrets.
2. Start Docker: docker-compose up -d.
3. Install deps: npm install.
4. Run dev server: npm run dev.

Endpoints:

• POST /auth/signup { username, password }
• POST /auth/login { username, password }
• POST /auth/refresh (cookie-based)
• POST /auth/logout
• GET /profile (protected)

Notes: In production set secure: true for cookies and serve over HTTPS.