Send cancel commands to workers

- Workers receive stop processing commands when jobs are cancelled
- Ensures workers halt processing immediately on cancel
- Maintains proper cleanup of resources

vidai/queue.py

@@ -72,12 +72,13 @@ class QueueManager:
         if job['status'] not in ['queued', 'processing']:
             return False
 
-        # If job was processing, clean up any active job for this queue_id
+        # If job was processing, send cancel command to worker and clean up active job
         if job['status'] == 'processing':
             from vidai.cluster_master import cluster_master
             for job_id, job_info in cluster_master.active_jobs.items():
                 if job_info.get('queue_id') == queue_id:
-                    cluster_master.complete_job(job_id)
+                    # Send cancel command to worker
+                    cluster_master._cancel_job_processing(job_id)
                     break
 
         # Update status to cancelled