refactor: mock清理+安全配置+通用组件+菜单优化

P0安全: SECRET_KEY/ADMIN_PASSWORD/CORS环境变量化, seed仅admin

P1Mock: mock.ts 301->88行, 删8数据mock+5generateMock, net-1300行

P2组件: useToast/useFetchList+ConfirmDialog/FormDialog

P3菜单: menuSections/menuItems->constants/menu.ts

P4API: NotificationsPage/WorkflowPage重写+RolesPage演示

测试: 1050passed, tsc clean

frontend/src/pages/InstancePage.tsx

@@ -154,17 +154,7 @@ export default function InstancePage() {
     try {
       const res = await instanceApi.list({});
       const data = Array.isArray(res) ? res : [];
-      /* Enrich with mock metrics for display */
-      const enriched = data.map((inst: InstanceItem, idx: number) => ({
-        ...inst,
-        connections: [245, 189, 192, 45, 23, 0, 156, 89, 1200, 1150, 340][idx] ?? 100,
-        qps: [3250, 2800, 2750, 120, 80, 0, 2100, 980, 45000, 42000, 1800][idx] ?? 500,
-        latency: [2.5, 3.1, 2.8, 15.2, 1.2, 0, 1.8, 8.5, 0.5, 0.6, 3.2][idx] ?? 5,
-        cpu: [45, 38, 40, 82, 15, 0, 35, 78, 25, 28, 42][idx] ?? 30,
-        memory: [68, 55, 58, 90, 30, 0, 60, 85, 75, 72, 65][idx] ?? 50,
-        disk: [72, 65, 68, 45, 25, 88, 55, 70, 10, 10, 60][idx] ?? 50,
-      }));
-      setInstances(enriched);
+      setInstances(data);
     } catch {
       /* keep existing */
     } finally {