Asynchronously patch many openings in a single call, commonly for HRIS integrations that close batches of headcount with status: "closed" and close_reason_id, or reconcile partner opening_id values after a sync. Each item follows the same shape as PATCH /v3/openings/{id} with an additional id key identifying the opening, and is processed independently. A bulk_action_uuid is returned immediately. Per-item success or failure is reported through GET /v3/bulk_requests/{bulk_action_uuid}.