fix(ui): 对齐所有页面样式到 Pencil 设计规范

transfer_page.dart:
- 金色主题统一（Light: secondary #F59E0B, Dark: primary #D4AF37）
- 修复交换按钮和确认按钮颜色

home_page.dart:
- Asset Card 圆角 14px
- 总资产字号 28px (displayLarge)
- "预估总资产"字号 13px (bodyLarge)
- 盈亏标签/数值字重调整

quick_actions_row.dart:
- padding 统一为 16px

welfare_center_page.dart:
- _statusBadge padding [6, 14]

trade_form_card.dart / price_card.dart:
- 样式细节对齐

flutter_monisuo/lib/ui/pages/trade/components/price_card.dart

@@ -23,7 +23,7 @@ class PriceCard extends StatelessWidget {
 
     return Container(
       width: double.infinity,
-      padding: const EdgeInsets.all(AppSpacing.md + AppSpacing.sm),
+      padding: const EdgeInsets.all(20), // 24px → 20px
       decoration: BoxDecoration(
         color: context.appColors.surfaceCard,
         borderRadius: BorderRadius.circular(AppRadius.lg),
@@ -45,7 +45,7 @@ class PriceCard extends StatelessWidget {
               // 涨跌幅徽章 - 圆角sm，涨绿背景
               Container(
                 padding: const EdgeInsets.symmetric(
-                    horizontal: AppSpacing.sm, vertical: AppSpacing.xs),
+                    horizontal: 8, vertical: 4), // 调整 padding
                 decoration: BoxDecoration(
                   color: changeBgColor,
                   borderRadius: BorderRadius.circular(AppRadius.sm),

flutter_monisuo/lib/ui/pages/trade/components/trade_form_card.dart

@@ -207,7 +207,7 @@ class TradeFormCard extends StatelessWidget {
         child: Container(
           height: 32,
           decoration: BoxDecoration(
-            color: context.colors.surfaceContainerHighest.withValues(alpha: 0.5),
+            color: context.colors.surfaceContainerHighest, // 移除 0.5 透明度
             borderRadius: BorderRadius.circular(AppRadius.sm),
           ),
           child: Center(