fix(settings): 日志保留时间移出顶部并紧凑化

通用配置卡内顺序改为 主题 → 语言 → 日志保留时间;保留时间从嵌套整卡
压缩为单行分区(标签 + 两个数字输入 + 内联保存),与主题/语言分区同族,
删去 desc 与两条 hint 冗余文案(中英同步)。

frontend/src/pages/settings/components/RetentionSection.tsx

@@ -2,7 +2,6 @@ import { memo, useCallback, useEffect, useState } from 'react'
 import { useTranslation } from 'react-i18next'
 import { Button } from '@/components/ui/button'
 import { Input } from '@/components/ui/input'
-import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card'
 import { systemApi, type RetentionSettings } from '@/api/system'
 import { toast } from 'sonner'
 
@@ -47,53 +46,39 @@ export const RetentionSection = memo(function RetentionSection() {
     }
   }, [settings, t])
 
+  // 紧凑单行分区(与主题/语言同族):标签 + 两个数字输入 + 内联保存,不再嵌套整卡
   return (
-    <Card>
-      <CardHeader className="pb-3">
-        <CardTitle className="text-base">{t('retention.title')}</CardTitle>
-        <p className="text-xs text-muted-foreground">{t('retention.desc')}</p>
-      </CardHeader>
-      <CardContent className="space-y-4">
-        <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
-          <div className="flex flex-col">
-            <label className="text-sm font-medium" htmlFor="retention-alert">
-              {t('retention.alertLabel')}
-            </label>
-            <Input
-              id="retention-alert"
-              type="number"
-              min={1}
-              max={365}
-              className="mt-1"
-              disabled={loading}
-              value={settings.alertDeliveryDays}
-              onChange={e => setSettings(s => ({ ...s, alertDeliveryDays: Number(e.target.value) || 0 }))}
-            />
-            <p className="mt-1 min-h-4 text-xs text-muted-foreground">{t('retention.alertHint')}</p>
-          </div>
-          <div className="flex flex-col">
-            <label className="text-sm font-medium" htmlFor="retention-audit">
-              {t('retention.auditLabel')}
-            </label>
-            <Input
-              id="retention-audit"
-              type="number"
-              min={1}
-              max={3650}
-              className="mt-1"
-              disabled={loading}
-              value={settings.auditLogDays}
-              onChange={e => setSettings(s => ({ ...s, auditLogDays: Number(e.target.value) || 0 }))}
-            />
-            <p className="mt-1 min-h-4 text-xs text-muted-foreground">{t('retention.auditHint')}</p>
-          </div>
-        </div>
-        <div className="flex justify-end">
-          <Button onClick={() => void save()} disabled={saving || loading}>
-            {saving ? t('retention.saving') : t('retention.save')}
-          </Button>
-        </div>
-      </CardContent>
-    </Card>
+    <div className="flex flex-wrap items-center gap-x-4 gap-y-2 border-t border-border pt-3">
+      <span className="min-w-14 shrink-0 text-sm text-muted-foreground">{t('retention.title')}</span>
+      <label className="flex items-center gap-1.5 text-xs text-muted-foreground" htmlFor="retention-alert">
+        {t('retention.alertLabel')}
+        <Input
+          id="retention-alert"
+          type="number"
+          min={1}
+          max={365}
+          className="h-8 w-20"
+          disabled={loading}
+          value={settings.alertDeliveryDays}
+          onChange={e => setSettings(s => ({ ...s, alertDeliveryDays: Number(e.target.value) || 0 }))}
+        />
+      </label>
+      <label className="flex items-center gap-1.5 text-xs text-muted-foreground" htmlFor="retention-audit">
+        {t('retention.auditLabel')}
+        <Input
+          id="retention-audit"
+          type="number"
+          min={1}
+          max={3650}
+          className="h-8 w-20"
+          disabled={loading}
+          value={settings.auditLogDays}
+          onChange={e => setSettings(s => ({ ...s, auditLogDays: Number(e.target.value) || 0 }))}
+        />
+      </label>
+      <Button size="sm" variant="outline" className="ml-auto" onClick={() => void save()} disabled={saving || loading}>
+        {saving ? t('retention.saving') : t('retention.save')}
+      </Button>
+    </div>
   )
 })

frontend/src/pages/settings/index.tsx

@@ -81,9 +81,9 @@ const SettingsPage = memo(function SettingsPage() {
             </CardTitle>
           </CardHeader>
           <CardContent className="space-y-3">
-            <RetentionSection />
             <ThemeSection />
             <LanguageSection />
+            <RetentionSection />
           </CardContent>
         </Card>