stability: avoid job lost between polls; serialize with 1 gunicorn worker

Dockerfile

@@ -50,6 +50,6 @@ ENV DJANGO_DEBUG=False \
 EXPOSE 7860
 
 # Run DB migrations at container start, then start gunicorn
-CMD ["sh", "-c", "python manage.py migrate --noinput && gunicorn core.wsgi:application --bind 0.0.0.0:${PORT} --workers 2 --threads 4 --timeout 120"]
+CMD ["sh", "-c", "python manage.py migrate --noinput && gunicorn core.wsgi:application --bind 0.0.0.0:${PORT} --workers 1 --threads 4 --timeout 120"]
 
 

backend/api/views.py

@@ -271,7 +271,12 @@ class ResultView(APIView):
 
         job = job_info['job']
         try:
-            status_name = job.status().code.name.lower()
+            try:
+                status_name = job.status().code.name.lower()
+            except Exception:
+                # If the client discarded the job (e.g., remote space returned 404 on queue),
+                # treat as finished to force a result fetch attempt which surfaces the error.
+                status_name = "finished"
             log_backend_message(f"ResultView: Job {job_id} status is '{status_name}'.")
             
             if status_name == "finished":