feat: add user registration and JWT authentication

- POST /auth/register - create account
- POST /auth/login - get JWT token
- GET /auth/me - get current user
- POST /auth/verify - verify token (for L1)
- Password hashing with bcrypt
- 30-day JWT tokens

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

requirements.txt

@@ -2,3 +2,5 @@ fastapi>=0.109.0
 uvicorn>=0.27.0
 requests>=2.31.0
 cryptography>=42.0.0
+passlib[bcrypt]>=1.7.4
+python-jose[cryptography]>=3.3.0