feat: complete E2E deployment flow with storage layered config and values template versioning

- Instance deployment: charts browser, deploy modal, instances list
- Values Template version management (create/history/rollback)
- Storage layered config (cluster > workspace > shared priority)
- Cluster credential decryptIfNeeded for mixed encrypted/plaintext kubeconfig
- YAML syntax validation (client-side + server-side warning)
- Frontend: charts, instances, storage, templates, admin pages
- Backend: storage service, instance service, cluster service, helm client
- Multi-Tenant Kubeconfig.md: added by user

backend/internal/adapter/input/http/rest/instance_handler.go

@@ -188,6 +188,7 @@ func (h *InstanceHandler) ListInstances(w http.ResponseWriter, r *http.Request)
 			LastOperation: string(instance.LastOperation),
 			LastError:     instance.LastError,
 			Revision:      instance.Revision,
+			Values:        instance.Values,
 			CreatedAt:     instance.CreatedAt.Format("2006-01-02T15:04:05Z07:00"),
 			UpdatedAt:     instance.UpdatedAt.Format("2006-01-02T15:04:05Z07:00"),
 		})