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/dto/chart_reference_dto.go

@@ -0,0 +1,31 @@
+package dto
+
+// CreateChartReferenceRequest 创建 Chart 引用请求
+type CreateChartReferenceRequest struct {
+	RegistryID  string `json:"registry_id" binding:"required"`
+	Repository  string `json:"repository" binding:"required"`
+	ChartName   string `json:"chart_name" binding:"required"`
+	Description string `json:"description"`
+}
+
+// UpdateChartReferenceRequest 更新 Chart 引用请求
+type UpdateChartReferenceRequest struct {
+	RegistryID  string `json:"registry_id"`
+	Repository  string `json:"repository"`
+	ChartName   string `json:"chart_name"`
+	Description string `json:"description"`
+	IsEnabled   *bool  `json:"is_enabled"`
+}
+
+// ChartReferenceResponse Chart 引用响应
+type ChartReferenceResponse struct {
+	ID          string `json:"id"`
+	WorkspaceID string `json:"workspace_id,omitempty"`
+	RegistryID  string `json:"registry_id"`
+	Repository  string `json:"repository"`
+	ChartName   string `json:"chart_name"`
+	Description string `json:"description"`
+	IsEnabled   bool   `json:"is_enabled"`
+	CreatedAt   string `json:"createdAt"`
+	UpdatedAt   string `json:"updatedAt"`
+}