refactor: change layout mode from mix to side

Changed layout from 'mix' to 'side' mode to optimize the layout structure to a left-right split layout. Also disabled default logo to prepare for custom logo component.

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

src/common/libs/umi/layoutConfig.tsx

@@ -33,9 +33,8 @@ export const LayoutConfig: RuntimeConfig['layout'] = () => {
 
   return {
     title: snap.session.campus?.name ?? '总后台',
-    // logo: <img src={Logo} style={{ height: '30px' }} />,
-    logo: <></>,
-    layout: 'mix',
+    logo: false, // 禁用默认logo，使用自定义
+    layout: 'side', // 从 'mix' 改为 'side'
     colorPrimary: '#1890ff',
     siderWidth: 220,
     pure: history.location.pathname === '/login',