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/artifact_service.go

@@ -68,6 +68,16 @@ func (s *ArtifactService) GetValuesSchema(ctx context.Context, registryID, repos
 	return s.ociClient.GetValuesSchema(ctx, registry, repository, reference)
 }
 
+// GetValues 获取 Helm Chart 的 values.yaml
+func (s *ArtifactService) GetValues(ctx context.Context, registryID, repository, reference string) (string, error) {
+	registry, err := s.registryRepo.GetByID(ctx, registryID)
+	if err != nil {
+		return "", entity.ErrRegistryNotFound
+	}
+
+	return s.ociClient.GetValues(ctx, registry, repository, reference)
+}
+
 // PullArtifact 下载 artifact
 func (s *ArtifactService) PullArtifact(ctx context.Context, registryID, repository, reference, destPath string) error {
 	registry, err := s.registryRepo.GetByID(ctx, registryID)