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/domain/repository/storage_repository.go

@@ -25,6 +25,12 @@ type StorageRepository interface {
 	// GetDefault 获取 workspace 的默认存储后端
 	GetDefault(ctx context.Context, workspaceID string) (*entity.StorageBackend, error)
 
+	// GetByCluster 获取 cluster 关联的存储后端列表
+	GetByCluster(ctx context.Context, clusterID string) ([]*entity.StorageBackend, error)
+
+	// GetDefaultByCluster 获取 cluster 的默认存储后端
+	GetDefaultByCluster(ctx context.Context, clusterID string) (*entity.StorageBackend, error)
+
 	// Update 更新存储后端
 	Update(ctx context.Context, storage *entity.StorageBackend) error