Asynchronously add many openings across one or more jobs in a single call, typically for HRIS sync workflows that open or extend headcount on a batch of requisitions. Each item follows the same shape as POST /v3/openings, with job_id required, 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}. The 100-open-openings-per-job limit still applies and is evaluated per item.