docs: relocate skills system documentation and refactor asset page components

Move skills system documentation from bottom to top of CLAUDE.md for better organization. Refactor Flutter asset page by extracting UI components into separate files and updating import structure for improved modularity.

flutter_monisuo/lib/ui/pages/mine/components/menu_group2.dart

@@ -0,0 +1,44 @@
+import 'package:flutter/material.dart';
+import 'package:lucide_icons_flutter/lucide_icons.dart';
+import 'menu_group_container.dart';
+import 'menu_row.dart';
+import 'menu_trailing_widgets.dart';
+
+/// 菜单分组2 - 深色模式 / 系统设置 / 关于我们
+class MenuGroup2 extends StatelessWidget {
+  final VoidCallback onShowAbout;
+
+  const MenuGroup2({super.key, required this.onShowAbout});
+
+  @override
+  Widget build(BuildContext context) {
+    final colorScheme = Theme.of(context).colorScheme;
+
+    return MenuGroupContainer(
+      child: Column(
+        children: [
+          // 深色模式
+          const DarkModeRow(),
+          const MenuDivider(),
+          // 系统设置
+          MenuRow(
+            icon: LucideIcons.settings,
+            iconColor: colorScheme.onSurfaceVariant,
+            title: '系统设置',
+            onTap: () {
+              // TODO: 系统设置
+            },
+          ),
+          const MenuDivider(),
+          // 关于我们
+          MenuRow(
+            icon: LucideIcons.info,
+            iconColor: colorScheme.onSurfaceVariant,
+            title: '关于我们',
+            onTap: onShowAbout,
+          ),
+        ],
+      ),
+    );
+  }
+}