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/adapter/input/http/rest/artifact_handler.go

@@ -191,3 +191,42 @@ func (h *ArtifactHandler) GetArtifactValuesSchema(w http.ResponseWriter, r *http
 
 	respondJSON(w, http.StatusOK, response)
 }
+
+// GetArtifactValues 获取 Helm Chart 的 values.yaml
+// @Summary 获取 Helm Chart Values
+// @Description 获取 Helm Chart 的 values.yaml 文件内容 (仅支持 Chart 类型)
+// @Tags Artifacts
+// @Accept json
+// @Produce json
+// @Param registry_id path string true "Registry ID"
+// @Param repository_name path string true "Repository Name (URL encoded)"
+// @Param reference path string true "Artifact Reference (tag or digest)"
+// @Success 200 {object} dto.ValuesResponse
+// @Failure 500 {object} dto.ErrorResponse
+// @Router /registries/{registry_id}/repositories/{repository_name}/artifacts/{reference}/values [get]
+func (h *ArtifactHandler) GetArtifactValues(w http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	registryID := vars["registry_id"]
+	repositoryName := vars["repository_name"]
+	reference := vars["reference"]
+
+	values, err := h.artifactService.GetValues(r.Context(), registryID, repositoryName, reference)
+	if err != nil {
+		switch {
+		case errors.Is(err, entity.ErrRegistryNotFound),
+			errors.Is(err, entity.ErrRepositoryNotFound),
+			errors.Is(err, entity.ErrArtifactNotFound),
+			errors.Is(err, entity.ErrValuesNotFound):
+			respondError(w, http.StatusNotFound, "Values not found", err.Error())
+		default:
+			respondError(w, http.StatusInternalServerError, "Failed to get values", err.Error())
+		}
+		return
+	}
+
+	response := &dto.ValuesResponse{
+		Values: values,
+	}
+
+	respondJSON(w, http.StatusOK, response)
+}