"""Authentication subsystem (JWT + API Key).

Modules:
- password: bcrypt hashing/verification
- models: SQLAlchemy 2 user/api-key/session models + init_auth_db
- jwt_utils: access/refresh token pair creation and verification
- middleware: AuthMiddleware (JWT + API Key dual-track)
- dependencies: FastAPI dependencies (get_current_user, require_authenticated)
"""