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/api/notification.ts

@@ -0,0 +1,9 @@
+import request from './request';
+
+export const notificationApi = {
+  list: () => request.get<any, any[]>('/notifications'),
+  create: (data: any) => request.post<any, any>('/notifications', data),
+  update: (id: number, data: any) => request.put<any, any>(`/notifications/${id}`, data),
+  delete: (id: number) => request.delete(`/notifications/${id}`),
+  test: (id: number) => request.post<any, any>(`/notifications/${id}/test`),
+};

frontend/src/api/workflow.ts

@@ -0,0 +1,11 @@
+import request from './request';
+
+export const workflowApi = {
+  list: () => request.get<any, any[]>('/workflows'),
+  get: (id: number) => request.get<any, any>(`/workflows/${id}`),
+  create: (data: any) => request.post<any, any>('/workflows', data),
+  update: (id: number, data: any) => request.put<any, any>(`/workflows/${id}`, data),
+  delete: (id: number) => request.delete(`/workflows/${id}`),
+  setDefault: (id: number) => request.post<any, any>(`/workflows/${id}/set-default`),
+  clone: (id: number) => request.post<any, any>(`/workflows/${id}/clone`),
+};