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/workspace_dto.go

@@ -0,0 +1,67 @@
+package dto
+
+import "time"
+
+// WorkspaceDTO 工作空间 DTO
+type WorkspaceDTO struct {
+	ID          string    `json:"id"`
+	Name        string    `json:"name"`
+	Description string    `json:"description,omitempty"`
+	CreatedBy   string    `json:"created_by"`
+	CreatedAt   time.Time `json:"created_at"`
+	UpdatedAt   time.Time `json:"updated_at"`
+}
+
+// CreateWorkspaceRequest 创建工作空间请求
+type CreateWorkspaceRequest struct {
+	Name        string `json:"name" validate:"required"`
+	Description string `json:"description"`
+}
+
+// UpdateWorkspaceRequest 更新工作空间请求
+type UpdateWorkspaceRequest struct {
+	Name        string `json:"name"`
+	Description string `json:"description"`
+}
+
+// QuotaDTO 配额 DTO
+type QuotaDTO struct {
+	ID           string  `json:"id"`
+	WorkspaceID  string  `json:"workspace_id"`
+	ResourceType string  `json:"resource_type"`
+	HardLimit    float64 `json:"hard_limit"`
+	SoftLimit    float64 `json:"soft_limit"`
+	Used         float64 `json:"used"`
+}
+
+// SetQuotaRequest 设置配额请求
+type SetQuotaRequest struct {
+	ResourceType string  `json:"resource_type" validate:"required"`
+	HardLimit    float64 `json:"hard_limit" validate:"required"`
+	SoftLimit    float64 `json:"soft_limit"`
+}
+
+// SetQuotasRequest 批量设置配额请求
+type SetQuotasRequest struct {
+	CPU        *QuotaValue `json:"cpu"`
+	GPU        *QuotaValue `json:"gpu"`
+	GPUMemory  *QuotaValue `json:"gpu_memory"`
+}
+
+// QuotaValue 配额值
+type QuotaValue struct {
+	HardLimit float64 `json:"hard_limit"`
+	SoftLimit float64 `json:"soft_limit"`
+}
+
+// WorkspaceResponse 工作空间响应
+type WorkspaceResponse struct {
+	Workspace *WorkspaceDTO `json:"workspace"`
+	Quotas    []*QuotaDTO   `json:"quotas,omitempty"`
+}
+
+// WorkspaceListResponse 工作空间列表响应
+type WorkspaceListResponse struct {
+	Workspaces []*WorkspaceDTO `json:"workspaces"`
+	Total      int             `json:"total"`
+}