feat(s2a): Add expandable group list with truncation in ProfileCard

- Add expanded state to ProfileCard component for toggling group visibility
- Implement MAX_VISIBLE constant to limit initial group display to 4 items
- Add toggle button to show/hide remaining groups with count indicator
- Display "收起" (collapse) when expanded, "+N 个分组" (N groups) when collapsed
- Wrap group grid in container div to accommodate expand/collapse button
- Improve UX for profiles with many groups by preventing excessive card height

frontend/src/pages/S2AConfig.tsx

@@ -598,10 +598,15 @@ function ProfileCard({ profile, isActive, isActivating, groupNameCache, onActiva
     onDelete: () => void
 }) {
     const [confirming, setConfirming] = useState(false)
+    const [expanded, setExpanded] = useState(false)
 
     let parsedGroups: number[] = []
     try { parsedGroups = JSON.parse(profile.group_ids || '[]') } catch { /* ignore */ }
 
+    const MAX_VISIBLE = 4
+    const visibleGroups = expanded ? parsedGroups : parsedGroups.slice(0, MAX_VISIBLE)
+    const hiddenCount = parsedGroups.length - MAX_VISIBLE
+
     return (
         <Card className={`relative transition-all flex flex-col h-full ${isActive ? 'ring-2 ring-green-500 dark:ring-green-400' : ''}`}>
             {/* 活动标记 */}
@@ -636,14 +641,24 @@ function ProfileCard({ profile, isActive, isActivating, groupNameCache, onActiva
 
                 {/* 分组列表 */}
                 {parsedGroups.length > 0 && (
-                    <div className="grid grid-cols-2 gap-2 mb-4">
+                    <div className="mb-4">
-                        {parsedGroups.map(id => (
+                        <div className="grid grid-cols-2 gap-2">
+                            {visibleGroups.map(id => (
                                 <div key={id} className="flex flex-col px-2.5 py-1.5 rounded-lg bg-blue-50 dark:bg-blue-900/20 border border-blue-100 dark:border-blue-800/40">
                                     <span className="text-xs font-medium text-blue-700 dark:text-blue-300 truncate">{groupNameCache[id] || `#${id}`}</span>
                                     {groupNameCache[id] && <span className="text-[10px] text-blue-400 dark:text-blue-500">#{id}</span>}
                                 </div>
                             ))}
                         </div>
+                        {hiddenCount > 0 && (
+                            <button
+                                onClick={() => setExpanded(!expanded)}
+                                className="mt-2 text-xs text-blue-500 hover:text-blue-700 dark:text-blue-400 dark:hover:text-blue-300 transition-colors"
+                            >
+                                {expanded ? '收起' : `+${hiddenCount} 个分组`}
+                            </button>
+                        )}
+                    </div>
                 )}
 
                 {/* 操作按钮 */}