feat(ui): 优化所有页面使用现代设计系统

- 使用 AppSpacing 替换硬编码间距
- 使用 AppRadius 替换硬编码圆角
- 使用 withValues(alpha:) 替换 withOpacity
- 优化 login_page, home_page, market_page, trade_page, asset_page, mine_page

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

flutter_monisuo/lib/ui/pages/market/market_page.dart

@@ -2,6 +2,8 @@ import 'package:flutter/material.dart';
 import 'package:shadcn_ui/shadcn_ui.dart';
 import 'package:provider/provider.dart';
 import '../../../core/constants/app_colors.dart';
+import '../../../core/theme/app_color_scheme.dart';
+import '../../../core/theme/app_spacing.dart';
 import '../../../data/models/coin.dart';
 import '../../../providers/market_provider.dart';
 
@@ -60,7 +62,7 @@ class _MarketPageState extends State<MarketPage> with AutomaticKeepAliveClientMi
     final theme = ShadTheme.of(context);
 
     return Padding(
-      padding: const EdgeInsets.all(16),
+      padding: AppSpacing.pagePadding,
       child: ShadInput(
         controller: _searchController,
         placeholder: const Text('搜索币种...'),
@@ -98,7 +100,7 @@ class _MarketPageState extends State<MarketPage> with AutomaticKeepAliveClientMi
 
     return Container(
       height: 44,
-      margin: const EdgeInsets.fromLTRB(16, 0, 16, 16),
+      margin: EdgeInsets.fromLTRB(AppSpacing.md, 0, AppSpacing.md, AppSpacing.md),
       child: Row(
         children: tabs.asMap().entries.map((entry) {
           final index = entry.key;
@@ -108,13 +110,13 @@ class _MarketPageState extends State<MarketPage> with AutomaticKeepAliveClientMi
           return GestureDetector(
             onTap: () => provider.setTab(tab['key']!),
             child: Container(
-              padding: const EdgeInsets.symmetric(horizontal: 20, vertical: 10),
-              margin: const EdgeInsets.only(right: 8),
+              padding: EdgeInsets.symmetric(horizontal: AppSpacing.lg + AppSpacing.xs, vertical: AppSpacing.sm + AppSpacing.xs),
+              margin: EdgeInsets.only(right: AppSpacing.sm),
               decoration: BoxDecoration(
                 color: isActive
                     ? theme.colorScheme.primary
                     : theme.colorScheme.card,
-                borderRadius: BorderRadius.circular(20),
+                borderRadius: BorderRadius.circular(AppRadius.xl),
               ),
               child: Text(
                 tab['label']!,
@@ -153,12 +155,12 @@ class _MarketPageState extends State<MarketPage> with AutomaticKeepAliveClientMi
               size: 48,
               color: theme.colorScheme.destructive,
             ),
-            const SizedBox(height: 12),
+            SizedBox(height: AppSpacing.sm + AppSpacing.xs),
             Text(
               provider.error!,
               style: TextStyle(color: theme.colorScheme.destructive),
             ),
-            const SizedBox(height: 16),
+            SizedBox(height: AppSpacing.md),
             ShadButton(
               onPressed: provider.loadCoins,
               child: const Text('重试'),
@@ -179,7 +181,7 @@ class _MarketPageState extends State<MarketPage> with AutomaticKeepAliveClientMi
               size: 48,
               color: theme.colorScheme.mutedForeground,
             ),
-            const SizedBox(height: 12),
+            SizedBox(height: AppSpacing.sm + AppSpacing.xs),
             Text(
               '暂无数据',
               style: theme.textTheme.muted,
@@ -193,7 +195,7 @@ class _MarketPageState extends State<MarketPage> with AutomaticKeepAliveClientMi
       onRefresh: provider.refresh,
       color: theme.colorScheme.primary,
       child: ListView.builder(
-        padding: const EdgeInsets.fromLTRB(16, 0, 16, 16),
+        padding: EdgeInsets.fromLTRB(AppSpacing.md, 0, AppSpacing.md, AppSpacing.md),
         itemCount: coins.length,
         itemBuilder: (context, index) => _buildCoinItem(coins[index]),
       ),
@@ -204,9 +206,9 @@ class _MarketPageState extends State<MarketPage> with AutomaticKeepAliveClientMi
     final theme = ShadTheme.of(context);
 
     return Padding(
-      padding: const EdgeInsets.only(bottom: 8),
+      padding: EdgeInsets.only(bottom: AppSpacing.sm),
       child: ShadCard(
-        padding: const EdgeInsets.all(16),
+        padding: AppSpacing.cardPadding,
         child: Row(
           children: [
             // 图标
@@ -221,7 +223,7 @@ class _MarketPageState extends State<MarketPage> with AutomaticKeepAliveClientMi
                 ),
               ),
             ),
-            const SizedBox(width: 12),
+            SizedBox(width: AppSpacing.sm + AppSpacing.xs),
             // 名称
             Expanded(
               child: Column(
@@ -242,15 +244,15 @@ class _MarketPageState extends State<MarketPage> with AutomaticKeepAliveClientMi
             ),
             // 涨跌幅
             Container(
-              padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 6),
+              padding: EdgeInsets.symmetric(horizontal: AppSpacing.sm + AppSpacing.xs, vertical: AppSpacing.xs + AppSpacing.xs),
               decoration: BoxDecoration(
-                color: AppColors.getChangeBackgroundColor(coin.isUp),
-                borderRadius: BorderRadius.circular(6),
+                color: getChangeBackgroundColor(coin.isUp),
+                borderRadius: BorderRadius.circular(AppRadius.sm + AppSpacing.xs),
               ),
               child: Text(
                 coin.formattedChange,
                 style: TextStyle(
-                  color: AppColors.getChangeColor(coin.isUp),
+                  color: getChangeColor(coin.isUp),
                   fontWeight: FontWeight.w600,
                 ),
               ),