refactor(frontend): P1-P2 架构统一 — utils/hooks/api 模块化

P1:
- utils/storage.ts、theme.ts、validate.ts + index 统一出口
- request/store/useTheme 接入 storage；清零 confirm/alert
- PipelineManager、TerminalAuditTab 拆分子模块（<700行红线）

P2:
- api/monitor、api/deploy 子目录化
- hooks/api 扩展：servers/pipelines/alerts/audit/sessionCommands
- PipelineManager、AuditOperationsTab 接入 TanStack Query

frontend/src/components/kubernetes/NamespaceManagementPage.tsx

@@ -16,6 +16,7 @@ import {
   Shield, Activity, AlertTriangle, CheckCircle2,
 } from 'lucide-react';
 import { kubernetesApi } from '@/api';
+import { toast } from 'sonner';
 
 interface NamespaceDetail {
   name: string;
@@ -75,7 +76,7 @@ export default function NamespaceManagementPage() {
       setCreateOpen(false);
       await loadData();
     } catch (err: any) {
-      alert(err?.message || '创建失败');
+      toast.error(err?.message || '创建失败');
     } finally {
       setCreating(false);
     }
@@ -89,7 +90,7 @@ export default function NamespaceManagementPage() {
       setDeleteTarget(null);
       await loadData();
     } catch (err: any) {
-      alert(err?.message || '删除失败');
+      toast.error(err?.message || '删除失败');
     } finally {
       setDeleting(false);
     }