refactor: full-stack restructure with multi-tenancy, workspace management, and K8s diagnostics

- Add Workspace domain (entity, repository, service, handler, DTO)
- Add multi-tenant K8s client with tenant binding and quota management
- Add K8s diagnostics client (instance diagnostics)
- Add authorization middleware (authz package)
- Restructure frontend to feature-based architecture (features/)
- Add User Management page in configuration
- Add AccessDenied page and route guards
- Refactor shared components (form inputs, layout, UI)
- Update Tailwind config for new design system
- Add comprehensive documentation (docs/, tasks/, plans)
- Improve cluster service with better kubeconfig handling
- Add tests for crypto, config, helm client, tenant binding

backend/internal/adapter/input/http/rest/cluster_handler.go

@@ -45,6 +45,11 @@ func (h *ClusterHandler) CreateCluster(w http.ResponseWriter, r *http.Request) {
 	// 创建实体
 	cluster := entity.NewCluster(req.Name, req.Host)
 	cluster.Description = req.Description
+	cluster.Visibility = req.Visibility
+	if req.GlobalShared || req.GlobalSharedAlt {
+		cluster.Visibility = "global_shared"
+	}
+	cluster.DefaultNamespace = req.DefaultNamespace
 
 	if req.CertData != "" && req.KeyData != "" {
 		cluster.SetCertAuth(req.CAData, req.CertData, req.KeyData)
@@ -147,6 +152,15 @@ func (h *ClusterHandler) UpdateCluster(w http.ResponseWriter, r *http.Request) {
 
 	// 更新字段
 	cluster.Update(req.Name, req.Host, req.Description)
+	if req.Visibility != "" {
+		cluster.Visibility = req.Visibility
+	}
+	if req.GlobalShared || req.GlobalSharedAlt {
+		cluster.Visibility = "global_shared"
+	}
+	if req.DefaultNamespace != "" {
+		cluster.DefaultNamespace = req.DefaultNamespace
+	}
 
 	if req.CertData != "" && req.KeyData != "" {
 		cluster.SetCertAuth(req.CAData, req.CertData, req.KeyData)