REFACTOR(app): use clustersecretstore for prod

- Change ExternalSecret to use ClusterSecretStore
- Remove SecretStore from kustomization

deploy/k8s/overlays/prod/externalsecret.yaml

@@ -6,7 +6,7 @@ spec:
   refreshInterval: 1h
   secretStoreRef:
     name: vault-backend
-    kind: SecretStore
+    kind: ClusterSecretStore
   target:
     name: todo-secrets
     creationPolicy: Owner

deploy/k8s/overlays/prod/kustomization.yaml

@@ -6,7 +6,6 @@ namespace: todo
 resources:
   - ../../base
   - resourcequota.yaml
-  - secretstore.yaml
   - externalsecret.yaml
   - ingress.yaml
 
@@ -16,7 +15,7 @@ commonLabels:
 # 이미지 태그 설정
 images:
   - name: ghcr.io/mayne0213/todo
-    newTag: main-sha-a81cf4fa21ba4efe71ec997680ad8e8bec46cb90
+    newTag: main-sha-6f03a0854ad55f7bc4bf4ecfa1c732df1ef16f8f
 
 patchesStrategicMerge:
   - deployment-patch.yaml