refactor: tighten shadcn admin ui polish

frontend/src/features/design-system/DesignSystemPreview.tsx

@@ -8,7 +8,7 @@ import { AppSection } from '@/components/app/AppSection'
 import { AppStatusBadge } from '@/components/app/AppStatusBadge'
 import { Badge } from '@/components/ui/badge'
 import { Button } from '@/components/ui/button'
-import { Card, CardContent, CardHeader } from '@/components/ui/card'
+import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card'
 import { Input } from '@/components/ui/input'
 import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@/components/ui/select'
 
@@ -37,13 +37,12 @@ export function DesignSystemPreview() {
       <div className="mx-auto flex max-w-6xl flex-col gap-6">
         <AppPageHeader
           title="设计系统预览"
-          description="业务页面必须基于 shadcn 原子组件和 App 组件层开发。"
           actions={<Button>创建工单</Button>}
         />
 
         <Card>
           <CardHeader>
-            <h2 className="text-sm font-medium">按钮</h2>
+            <CardTitle className="text-sm">按钮</CardTitle>
           </CardHeader>
           <CardContent className="flex flex-wrap gap-2">
             <Button>主要操作</Button>
@@ -55,7 +54,7 @@ export function DesignSystemPreview() {
 
         <Card>
           <CardHeader>
-            <h2 className="text-sm font-medium">状态与优先级</h2>
+            <CardTitle className="text-sm">状态与优先级</CardTitle>
           </CardHeader>
           <CardContent className="flex flex-wrap gap-2">
             <Badge>默认</Badge>
@@ -88,17 +87,16 @@ export function DesignSystemPreview() {
           rows={previewRows}
           getRowKey={(row) => row.id}
           emptyTitle="暂无数据"
-          emptyDescription="符合条件的数据会显示在这里。"
         />
 
         <AppDetailLayout
           side={
-            <AppSection title="右侧面板" description="用于关键字段、关联方案和 AI 分析。">
-              <AppEmptyState title="等待接入" description="后续阶段会接入 Agent 执行结果。" />
+            <AppSection title="右侧面板">
+              <AppEmptyState title="等待接入" />
             </AppSection>
           }
         >
-          <AppSection title="详情区块" description="用于承载工单概览、问题描述和处理动态。">
+          <AppSection title="详情区块">
             <p className="text-sm text-muted-foreground">页面级布局只复用 App 组件，业务字段由页面自行传入。</p>
           </AppSection>
         </AppDetailLayout>