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/entity/storage.go

@@ -43,6 +43,7 @@ type HostPathConfig struct {
 type StorageBackend struct {
 	ID          string
 	WorkspaceID string
+	ClusterID   string // 关联的 cluster，NULL 表示 workspace/shared 级别
 	OwnerID     string
 	Name        string
 	Type        StorageType
@@ -70,6 +71,13 @@ func NewStorageBackend(workspaceID, ownerID, name string, storageType StorageTyp
 	}
 }
 
+// NewClusterStorageBackend 创建 cluster 级别的存储后端
+func NewClusterStorageBackend(workspaceID, clusterID, ownerID, name string, storageType StorageType, config StorageConfig) *StorageBackend {
+	storage := NewStorageBackend(workspaceID, ownerID, name, storageType, config)
+	storage.ClusterID = clusterID
+	return storage
+}
+
 // Validate 验证存储后端数据
 func (s *StorageBackend) Validate() error {
 	if s.Name == "" {