fix(ui): 修复主题切换功能，支持明暗主题动态切换

- 替换所有硬编码颜色为动态颜色
- 所有页面使用 Theme.of(context) 获取主题颜色
- 支持深色和浅色主题切换
- 修复 GlassPanel 和 NeonGlow 组件的主题适配
- 完善 lightMaterial ColorScheme 定义
- 测试主题切换功能正常

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

flutter_monisuo/lib/ui/components/asset_card.dart

@@ -22,8 +22,10 @@ class AssetCard extends StatelessWidget {
   final VoidCallback? onTap;
 
   /// 默认渐变色 - Neon Blue → Electric Purple
-  static const defaultGradient = LinearGradient(
-    colors: [AppColorScheme.darkPrimary, AppColorScheme.darkSecondary],
+  static LinearGradient defaultGradientBuilder(bool isDark) => LinearGradient(
+    colors: isDark
+        ? [AppColorScheme.darkPrimary, AppColorScheme.darkSecondary]
+        : [AppColorScheme.lightPrimary, AppColorScheme.lightSecondary],
     begin: Alignment.topLeft,
     end: Alignment.bottomRight,
   );
@@ -50,7 +52,8 @@ class AssetCard extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     final theme = ShadTheme.of(context);
-    final cardGradient = gradient ?? defaultGradient;
+    final isDark = Theme.of(context).brightness == Brightness.dark;
+    final cardGradient = gradient ?? defaultGradientBuilder(isDark);
 
     return GestureDetector(
       onTap: onTap,