Api Annotation Items Bulk Create

POST /api/annotation-items/bulk/ Bulk create annotation items (assign logs to workers). Supports both "by-reference" and "by-direct-payload" methods. Permission: Requires annotation_items:create (admin only) Events: `annotation_item_assigned` dispatched via signals (see annotation/signals.py) Request Body: { "assignee_id": "user_123", "source_items": [ {"source_type": "logs", "log_id": "log_1"}, {"source_type": "logs", "log_id": "log_2", "full_object": {...}} ] } Response (201) — canonical BulkOperationResponse envelope with the pre-foundation custom fields (`created_count`, `items`) carried as extras via Pydantic ``extra="allow"``: { "success_count": 2, "error_count": 0, "errors": [], "created_count": 2, "items": [...] }