Delete a terminal eval run
Hard-delete a terminal eval run; its scores cascade (ORM
delete-orphan + DB FK ON DELETE CASCADE).
Terminal-only allow-list: rejects (409) anything not
completed/failed/errored — so pending/running and any future
non-terminal state are blocked. Cross-org/unknown → 404. get_session()
auto-commits on success.
DELETE
Delete a terminal eval run
Delete a terminal eval run