fix(group): 分组面包屑保留详情页外框

用 Card.detail-nav 包裹 Breadcrumb，和条目/图文详情页一致

stash-web/src/AppNext.tsx

@@ -1,5 +1,6 @@
 import {
   Breadcrumb,
+  Card,
   Empty,
   EngineIcon,
   Layout,
@@ -607,6 +608,7 @@ export default function AppNext() {
 
     return (
       <div className="detail-view">
+        <Card padding="none" className="detail-nav">
           <Breadcrumb
             className="detail-breadcrumb"
             items={[
@@ -618,6 +620,7 @@ export default function AppNext() {
             ]}
             onNavigate={navigate}
           />
+        </Card>
 
         <div className="detail-hero">
           <span className="detail-hero-icon" aria-hidden="true">