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/index.css

@@ -186,3 +186,14 @@
     background: #9ca3af;
   }
 }
+
+@keyframes fadeInUp {
+  from {
+    opacity: 0;
+    transform: translateY(8px);
+  }
+  to {
+    opacity: 1;
+    transform: translateY(0);
+  }
+}