Fix Celery Upstash Redis SSL compatibility

backend/app/worker/celery_app.py

@@ -1,10 +1,15 @@
 from celery import Celery
 from app.core.config import settings
 
+redis_url = settings.REDIS_URL
+if redis_url.startswith("rediss://") and "ssl_cert_reqs=" not in redis_url:
+    delimiter = "&" if "?" in redis_url else "?"
+    redis_url = f"{redis_url}{delimiter}ssl_cert_reqs=CERT_NONE"
+
 celery_app = Celery(
     "worker",
-    broker=settings.REDIS_URL,
-    backend=settings.REDIS_URL,
+    broker=redis_url,
+    backend=redis_url,
     include=["app.worker.tasks"]
 )