refactor: 迁移 UI 组件库从 Ant Design 至 TDesign

- 替换 antd 为 tdesign-react 作为主要 UI 组件库
- 引入 Recharts 替代 @ant-design/charts 实现图表功能
- 移除主题系统相关代码（ThemeContext、themes 目录）
- 更新所有组件以适配 TDesign 组件 API
- 更新测试用例以匹配新的组件实现
- 新增 TDesign 和 Recharts 集成规范文档

frontend/src/pages/Settings/index.tsx

@@ -1,40 +1,11 @@
-import { Card, Select, Switch, Space, Typography } from 'antd';
-import { useTheme } from '@/contexts/ThemeContext';
-import { themeOptions, type ThemeId } from '@/themes';
-
-const { Text } = Typography;
+import { Card } from 'tdesign-react';
 
 export function SettingsPage() {
-  const { themeId, followSystem, setThemeId, setFollowSystem } = useTheme();
-
   return (
-    <Space vertical size="large" style={{ width: '100%' }}>
-      <Card title="主题">
-        <Space vertical size="middle" style={{ width: '100%' }}>
-          <div style={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center' }}>
-            <div>
-              <Text strong>主题</Text>
-            </div>
-            <Select
-              value={themeId}
-              onChange={(value: ThemeId) => setThemeId(value)}
-              style={{ width: 180 }}
-              options={themeOptions.map((opt) => ({
-                value: opt.id,
-                label: opt.label,
-              }))}
-            />
-          </div>
-          <div style={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center' }}>
-            <div>
-              <Text strong>跟随系统</Text>
-              <br />
-              <Text type="secondary">开启后自动跟随系统暗色模式</Text>
-            </div>
-            <Switch checked={followSystem} onChange={setFollowSystem} />
-          </div>
-        </Space>
-      </Card>
-    </Space>
+    <Card title="设置">
+      <div style={{ textAlign: 'center', padding: '40px 0', color: '#999' }}>
+        设置功能开发中...
+      </div>
+    </Card>
   );
 }