fix(edu): run redis as statefulset

Keep the existing Redis PVC and data while migrating the edu-master workload from Deployment to StatefulSet.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

edu_master/k8s/redis.yaml

@@ -1,11 +1,12 @@
 apiVersion: apps/v1
-kind: Deployment
+kind: StatefulSet
 metadata:
   name: redis
   namespace: edu-master
   labels:
     app: edu-master-redis
 spec:
+  serviceName: redis
   replicas: 1
   selector:
     matchLabels: