Hard-delete a detector; its existing findings stay readable.

Requires MEMBER role or higher in the project's workspace (the write service decides). Not idempotent: a second delete of the same id is a 404.

Args: request (Request): Incoming request (rate-limit plumbing). response (Response): Outgoing response (rate-limit plumbing). auth (AccountStampedAuth): Account-scope user auth (session token or CLI access JWT); its resolved user_id becomes the actor. detector_id (str): The detector to delete. project_id (str): The project the detector belongs to. reason (str): Why it is being deleted; recorded on the audit row. _live (None): Write-path liveness gate (blocks a revoked JWT session).

Returns: DeleteDetectorResponse: The removed detector.

Raises: HTTPException: The write service's 400/403/404 verbatim, or a 503 when its response is ambiguous.