feat(frontend): add Helm chart browser, monitoring, chart-references and values templates pages

Add new frontend pages for the multi-tenant OCDP platform:

- Charts page (/charts): Browse Harbor OCI registries to list Helm chart repositories
  and versions, with deploy modal to launch charts on selected clusters
- Monitoring page (/monitoring): Display cluster metrics (CPU/Memory/GPU usage)
  and per-node details with resource utilization bars
- Chart References page (/chart-references): CRUD for chart metadata references
- Values Templates page (/templates): CRUD for Helm values templates with version
  history and rollback support
- Sidebar: Add Charts navigation, update Storage and Templates links
- api.ts: Add all API client functions (clusterApi, registryApi, instanceApi,
  monitoringApi, storageApi, chartReferenceApi, valuesTemplateApi,
  workspaceApi, userApi) with full TypeScript types

Note: deploy flow and values template rollback not yet end-to-end tested.

backend/internal/domain/service/storage_service.go

@@ -0,0 +1,116 @@
+package service
+
+import (
+	"context"
+	"errors"
+
+	"github.com/ocdp/cluster-service/internal/domain/entity"
+	"github.com/ocdp/cluster-service/internal/domain/repository"
+)
+
+var (
+	ErrStorageNotFound = errors.New("storage backend not found")
+	ErrStorageExists   = errors.New("storage backend already exists")
+)
+
+// StorageService 存储后端领域服务
+type StorageService struct {
+	storageRepo repository.StorageRepository
+}
+
+// NewStorageService 创建存储后端服务
+func NewStorageService(storageRepo repository.StorageRepository) *StorageService {
+	return &StorageService{
+		storageRepo: storageRepo,
+	}
+}
+
+// Create 创建存储后端
+func (s *StorageService) Create(
+	ctx context.Context,
+	workspaceID, ownerID, name string,
+	storageType entity.StorageType,
+	config entity.StorageConfig,
+	description string,
+	isDefault, isShared bool,
+) (*entity.StorageBackend, error) {
+	// 检查名称是否已存在
+	existing, _ := s.storageRepo.GetByName(ctx, workspaceID, name)
+	if existing != nil {
+		return nil, ErrStorageExists
+	}
+
+	storage := entity.NewStorageBackend(workspaceID, ownerID, name, storageType, config)
+	storage.Description = description
+	storage.IsDefault = isDefault
+	storage.IsShared = isShared
+
+	if err := s.storageRepo.Create(ctx, storage); err != nil {
+		return nil, err
+	}
+
+	return storage, nil
+}
+
+// GetByID 获取存储后端
+func (s *StorageService) GetByID(ctx context.Context, id string) (*entity.StorageBackend, error) {
+	storage, err := s.storageRepo.GetByID(ctx, id)
+	if err != nil {
+		return nil, ErrStorageNotFound
+	}
+	return storage, nil
+}
+
+// GetByWorkspace 获取工作空间的所有存储后端
+func (s *StorageService) GetByWorkspace(ctx context.Context, workspaceID string) ([]*entity.StorageBackend, error) {
+	return s.storageRepo.GetByWorkspace(ctx, workspaceID)
+}
+
+// GetShared 获取所有共享存储后端
+func (s *StorageService) GetShared(ctx context.Context) ([]*entity.StorageBackend, error) {
+	return s.storageRepo.GetShared(ctx)
+}
+
+// GetDefault 获取工作空间的默认存储后端
+func (s *StorageService) GetDefault(ctx context.Context, workspaceID string) (*entity.StorageBackend, error) {
+	return s.storageRepo.GetDefault(ctx, workspaceID)
+}
+
+// Update 更新存储后端
+func (s *StorageService) Update(
+	ctx context.Context,
+	id, name, description string,
+	storageType entity.StorageType,
+	config entity.StorageConfig,
+	isDefault, isShared bool,
+) (*entity.StorageBackend, error) {
+	storage, err := s.storageRepo.GetByID(ctx, id)
+	if err != nil {
+		return nil, ErrStorageNotFound
+	}
+
+	if name != "" {
+		storage.Name = name
+	}
+	storage.Description = description
+	storage.Type = storageType
+	storage.Config = config
+	storage.IsDefault = isDefault
+	storage.IsShared = isShared
+
+	if err := s.storageRepo.Update(ctx, storage); err != nil {
+		return nil, err
+	}
+
+	return storage, nil
+}
+
+// Delete 删除存储后端
+func (s *StorageService) Delete(ctx context.Context, id string) error {
+	return s.storageRepo.Delete(ctx, id)
+}
+
+// List 列出所有存储后端（管理员用）
+func (s *StorageService) List(ctx context.Context) ([]*entity.StorageBackend, error) {
+	return s.storageRepo.List(ctx)
+}