refactor: 重构后端目录结构和命名规范

- 将后端目录名从大写改为小写 (Controller->controller 等)
- 将命名空间从 App\ 改为 app\ (符合 webman 官方规范)
- 移除不必要的 bootstrap 目录
- 完善出差审批业务功能：
  - 添加删除草稿功能
  - 添加审批操作功能（同意/拒绝）
  - 完善审批详情页，显示审批人和审批记录
- 前端优化：
  - 调整列表页行高
  - 隐藏底部导航栏
  - 仪表盘只显示3个快捷入口

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/router/index.tsx

@@ -1,14 +1,13 @@
 import { createBrowserRouter, Navigate } from 'react-router-dom'
 import MobileLayout from '@/components/layout/MobileLayout'
 import Dashboard from '@/pages/dashboard'
-import Apps from '@/pages/apps'
 import BusinessTripList from '@/pages/business-trip/list'
 import BusinessTripApply from '@/pages/business-trip/apply'
 import BusinessTripDetail from '@/pages/business-trip/detail'
 import SelectApprover from '@/pages/business-trip/select-approver'
 import SelectCc from '@/pages/business-trip/select-cc'
-import Profile from '@/pages/profile'
 import Login from '@/pages/login'
+import SimpleLogin from '@/pages/login-simple'
 
 const router = createBrowserRouter([
   {
@@ -17,16 +16,15 @@ const router = createBrowserRouter([
     children: [
       { index: true, element: <Navigate to='/dashboard' replace /> },
       { path: 'dashboard', element: <Dashboard /> },
-      { path: 'apps', element: <Apps /> },
       { path: 'business-trip', element: <BusinessTripList /> },
       { path: 'business-trip/apply', element: <BusinessTripApply /> },
       { path: 'business-trip/apply/select-approver', element: <SelectApprover /> },
       { path: 'business-trip/apply/select-cc', element: <SelectCc /> },
       { path: 'business-trip/:id', element: <BusinessTripDetail /> },
-      { path: 'profile', element: <Profile /> },
     ],
   },
   { path: '/login', element: <Login /> },
+  { path: '/login-simple', element: <SimpleLogin /> },
   { path: '*', element: <Navigate to='/dashboard' replace /> },
 ])