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,
@@ -607,17 +608,19 @@ export default function AppNext() {
 
     return (
       <div className="detail-view">
-        <Breadcrumb
-          className="detail-breadcrumb"
-          items={[
-            { label: '首页', href: '/' },
-            ...trail.map((node) => ({
-              label: node.title,
-              href: `/g/${encodeURIComponent(node.key)}`,
-            })),
-          ]}
-          onNavigate={navigate}
-        />
+        <Card padding="none" className="detail-nav">
+          <Breadcrumb
+            className="detail-breadcrumb"
+            items={[
+              { label: '首页', href: '/' },
+              ...trail.map((node) => ({
+                label: node.title,
+                href: `/g/${encodeURIComponent(node.key)}`,
+              })),
+            ]}
+            onNavigate={navigate}
+          />
+        </Card>
 
         <div className="detail-hero">
           <span className="detail-hero-icon" aria-hidden="true">