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/repository/workspace_repository.go

@@ -0,0 +1,27 @@
+package repository
+
+import (
+	"context"
+	"github.com/ocdp/cluster-service/internal/domain/entity"
+)
+
+// WorkspaceRepository Workspace 仓储接口
+type WorkspaceRepository interface {
+	// Create 创建 Workspace
+	Create(ctx context.Context, workspace *entity.Workspace) error
+
+	// GetByID 根据 ID 获取 Workspace
+	GetByID(ctx context.Context, id string) (*entity.Workspace, error)
+
+	// GetByName 根据名称获取 Workspace
+	GetByName(ctx context.Context, name string) (*entity.Workspace, error)
+
+	// Update 更新 Workspace
+	Update(ctx context.Context, workspace *entity.Workspace) error
+
+	// Delete 删除 Workspace
+	Delete(ctx context.Context, id string) error
+
+	// List 列出所有 Workspace
+	List(ctx context.Context) ([]*entity.Workspace, error)
+}