💄 style(components): 更新统计卡片图标样式

- 将TrendingUpOutlined和TrendingDownOutlined替换为ArrowUpOutlined和ArrowDownOutlined，统一图标风格

♻️ refactor(routes): 优化页面导入方式

- 移除DashboardPage导入时的花括号，与其他页面导入方式保持一致

src/client/admin/components/TechStatCard.tsx

@@ -1,6 +1,6 @@
 import React from 'react';
 import { Card } from 'antd';
-import { TrendingUpOutlined, TrendingDownOutlined } from '@ant-design/icons';
+import { ArrowUpOutlined, ArrowDownOutlined } from '@ant-design/icons';
 import type { ReactNode } from 'react';
 
 interface TechStatCardProps {
@@ -24,7 +24,7 @@ export const TechStatCard: React.FC<TechStatCardProps> = ({
 }) => {
   const isPositive = trend !== undefined && trend > 0;
   const trendColor = isPositive ? 'text-green-400' : 'text-red-400';
-  const TrendIcon = isPositive ? TrendingUpOutlined : TrendingDownOutlined;
+  const TrendIcon = isPositive ? ArrowUpOutlined : ArrowDownOutlined;
 
   return (
     <div className="relative group">

src/client/admin/routes.tsx

@@ -4,7 +4,7 @@ import { ProtectedRoute } from './components/ProtectedRoute';
 import { MainLayout } from './layouts/MainLayout';
 import { ErrorPage } from './components/ErrorPage';
 import { NotFoundPage } from './components/NotFoundPage';
-import { DashboardPage } from './pages/Dashboard';
+import DashboardPage from './pages/Dashboard';
 import { UsersPage } from './pages/Users';
 import { LoginPage } from './pages/Login';
 import { FilesPage } from './pages/Files';