Generate Agent Api Key

Generate or rotate the SDK API key for an agent.

If an active (non-revoked) key already exists for the agent, this endpoint revokes it and inserts a new active row in a single transaction. The new full_key is returned exactly once in the response; the plaintext secret is never persisted server-side, only its bcrypt hash.

Args: agent_id: Path parameter; the target agent's primary key. current_user: Resolved from the Authorization: Bearer <JWT> header by get_current_user. db: SQLAlchemy session injected by FastAPI.

Returns: :class:APIKeyGenerateResponse containing full_key (one-shot plaintext), key_prefix, and created_at.

Raises: HTTPException 401: missing or invalid JWT. HTTPException 404: agent does not exist or does not belong to the caller (deliberate to avoid leaking agent existence). HTTPException 500: any unexpected error; transaction rolled back. The most plausible internal failure is a partial-unique index violation from a concurrent POST race, which the DB enforces.

Notes: - Transactional shape mirrors auth.setup_admin and custom_api.create_custom_api -- we collect all writes in the session and commit once. There is no SELECT ... FOR UPDATE; concurrent rotations are caught by the uq_agent_api_keys_agent_active partial unique index and surfaced as a 500. Two clients racing to rotate the same key is a corner case; a 500 is acceptable. - Logs include the key_prefix only -- never the full_key, the secret half, or the bcrypt hash.