refactor(mp): 迁移商城+AI报告+预约列表+文章详情页 — 统一组件库

商城订单/积分兑换/积分明细、AI 报告列表、预约列表、
文章详情共 6 个页面迁移：
- 最外层容器 → PageShell
- SCSS 删除 min-height/background 通用样式

apps/miniprogram/src/pages/pkg-mall/exchange/index.tsx

@@ -11,6 +11,7 @@ import { usePointsStore } from '../../../stores/points';
 import Loading from '../../../components/Loading';
 import { useElderClass } from '../../../hooks/useElderClass';
 import { useSafeTimeout } from '@/hooks/useSafeTimeout';
+import PageShell from '@/components/ui/PageShell';
 import './index.scss';
 
 const TYPE_INITIAL: Record<string, string> = {
@@ -128,9 +129,9 @@ export default function ExchangeConfirm() {
 
   if (loading) {
     return (
-      <View className={`exchange-page ${modeClass}`}>
+      <PageShell className={modeClass}>
         <Loading />
-      </View>
+      </PageShell>
     );
   }
 
@@ -140,7 +141,7 @@ export default function ExchangeConfirm() {
   const iconCls = TYPE_CLASS[productType] || 'product-icon-wrap--service';
 
   return (
-    <View className={`exchange-page ${modeClass}`}>
+    <PageShell className={modeClass}>
       {/* 商品预览卡片 */}
       <View className='product-card'>
         <View className={`product-icon-wrap ${iconCls}`}>
@@ -216,6 +217,6 @@ export default function ExchangeConfirm() {
           </Text>
         </View>
       </View>
-    </View>
+    </PageShell>
   );
 }