refactor(settings): simplify settings component and implement redirect

- Removed the MainPageLayout and its associated components from the settings page, returning null instead.
- Added a loader function to redirect users to the '/settings/site' path, streamlining navigation within the application.

Signed-off-by: Innei <tukon479@gmail.com>

be/apps/dashboard/src/pages/(main)/settings/index.tsx

@@ -1,13 +1,7 @@
-import { MainPageLayout } from '~/components/layouts/MainPageLayout'
-import { SettingsForm, SettingsNavigation } from '~/modules/settings'
+import { redirect } from 'react-router'
 
 export function Component() {
-  return (
-    <MainPageLayout title="系统设置" description="管理后台与核心功能的通用配置，修改后会立即同步生效。">
-      <div className="space-y-6">
-        <SettingsNavigation active="site" />
-        <SettingsForm />
-      </div>
-    </MainPageLayout>
-  )
+  return null
 }
+
+export const loader = () => redirect('/settings/site')