fix(profile): 修复伞下树图未居中问题

使用 LayoutBuilder 获取实际容器宽度而不是屏幕宽度

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/mobile-app/lib/features/profile/presentation/widgets/team_tree_widget.dart

@@ -81,23 +81,28 @@ class _TeamTreeWidgetState extends State<TeamTreeWidget> {
 
   @override
   Widget build(BuildContext context) {
-    final screenWidth = MediaQuery.of(context).size.width;
+    return LayoutBuilder(
+      builder: (context, constraints) {
+        // 使用实际容器宽度而不是屏幕宽度
+        final containerWidth = constraints.maxWidth;
 
-    return SingleChildScrollView(
-      scrollDirection: Axis.horizontal,
-      child: SingleChildScrollView(
-        child: ConstrainedBox(
-          constraints: BoxConstraints(
-            minWidth: screenWidth,
-          ),
-          child: Center(
-            child: Padding(
-              padding: const EdgeInsets.symmetric(horizontal: 16),
-              child: _buildTreeLevel([widget.rootNode], 0),
+        return SingleChildScrollView(
+          scrollDirection: Axis.horizontal,
+          child: SingleChildScrollView(
+            child: ConstrainedBox(
+              constraints: BoxConstraints(
+                minWidth: containerWidth,
+              ),
+              child: Center(
+                child: Padding(
+                  padding: const EdgeInsets.symmetric(horizontal: 8),
+                  child: _buildTreeLevel([widget.rootNode], 0),
+                ),
+              ),
             ),
           ),
-        ),
-      ),
+        );
+      },
     );
   }