feat: UI 清新风全面改造 — 朝露主题 + shadcn_ui + 全局字号放大

- 全新"朝露"主题：深青绿主色(#2D6A4F)，暖白底，完整设计Token
- 引入 shadcn_ui 组件库，MaterialApp 注入 ShadTheme
- 新增 4 个公共组件：AppCard、AppMenuItem、AppEmptyState、AppTabChip
- 全面消除硬编码颜色，统一使用 AppTheme Token
- 全局字号 +3~4pt，图标等比放大 +3px
- home/medication/profile/settings/login 等核心页面重写
- 路由和功能逻辑零改动

health_app/lib/pages/settings/notification_prefs_page.dart

@@ -1,4 +1,5 @@
 import 'package:flutter/material.dart';
+import '../../core/app_theme.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import '../../core/navigation_provider.dart';
 
@@ -49,7 +50,7 @@ class NotificationPrefsPage extends ConsumerWidget {
     final dndOn = prefs['dndEnabled'] ?? false;
 
     return Scaffold(
-      backgroundColor: const Color(0xFFF8F9FC),
+      backgroundColor: AppTheme.bg,
       appBar: AppBar(
         backgroundColor: Colors.transparent,
         elevation: 0,
@@ -57,7 +58,7 @@ class NotificationPrefsPage extends ConsumerWidget {
           icon: const Icon(Icons.arrow_back_ios_new, color: Color(0xFF1A1A1A)),
           onPressed: () => popRoute(ref),
         ),
-        title: const Text('消息通知', style: TextStyle(fontSize: 18, fontWeight: FontWeight.w600, color: Color(0xFF1A1A1A))),
+        title: const Text('消息通知', style: TextStyle(fontSize: 21, fontWeight: FontWeight.w600, color: Color(0xFF1A1A1A))),
         centerTitle: true,
       ),
       body: SingleChildScrollView(
@@ -89,7 +90,7 @@ class NotificationPrefsPage extends ConsumerWidget {
             _SwitchTile(
               icon: Icons.warning_amber_rounded,
               iconBg: const Color(0xFFFFEBEE),
-              iconColor: const Color(0xFFE53935),
+              iconColor: AppTheme.error,
               title: '健康异常提醒',
               subtitle: '检测到数据异常时及时通知',
               value: prefs['healthAlert'] ?? true,
@@ -107,7 +108,7 @@ class NotificationPrefsPage extends ConsumerWidget {
             _SwitchTile(
               icon: Icons.smart_toy_outlined,
               iconBg: const Color(0xFFF3E5F5),
-              iconColor: const Color(0xFF8B9CF7),
+              iconColor: AppTheme.primary,
               title: 'AI 回复通知',
               subtitle: 'AI 助手回复时发送通知',
               value: prefs['aiReply'] ?? false,
@@ -133,7 +134,7 @@ class NotificationPrefsPage extends ConsumerWidget {
                     final picked = await showTimePicker(context: context, initialTime: const TimeOfDay(hour: 22, minute: 0));
                     if (picked != null && context.mounted) ref.read(notificationPrefsProvider.notifier).setDndStart(picked);
                   })),
-                  Padding(padding: const EdgeInsets.symmetric(horizontal: 12), child: Text('~', style: TextStyle(fontSize: 16, color: Colors.grey[400]))),
+                  Padding(padding: const EdgeInsets.symmetric(horizontal: 12), child: Text('~', style: TextStyle(fontSize: 19, color: Colors.grey[400]))),
                   Expanded(child: _TimeButton(label: '结束', time: '08:00', onTap: () async {
                     final picked = await showTimePicker(context: context, initialTime: const TimeOfDay(hour: 8, minute: 0));
                     if (picked != null && context.mounted) ref.read(notificationPrefsProvider.notifier).setDndEnd(picked);
@@ -157,7 +158,7 @@ class _SectionTitle extends StatelessWidget {
   const _SectionTitle({required this.title});
   @override
   Widget build(BuildContext context) {
-    return Padding(padding: const EdgeInsets.only(left: 4, bottom: 10), child: Text(title, style: const TextStyle(fontSize: 14, fontWeight: FontWeight.w600, color: Color(0xFF999999))));
+    return Padding(padding: const EdgeInsets.only(left: 4, bottom: 10), child: Text(title, style: const TextStyle(fontSize: 17, fontWeight: FontWeight.w600, color: Color(0xFF999999))));
   }
 }
 
@@ -186,14 +187,14 @@ class _SwitchTile extends StatelessWidget {
       decoration: BoxDecoration(color: Colors.white, borderRadius: BorderRadius.circular(12)),
       child: Row(children: [
         if (icon != null) ...[
-          Container(width: 38, height: 38, decoration: BoxDecoration(color: iconBg, borderRadius: BorderRadius.circular(10)), child: Icon(icon, size: 20, color: iconColor)),
+          Container(width: 38, height: 38, decoration: BoxDecoration(color: iconBg, borderRadius: BorderRadius.circular(10)), child: Icon(icon, size: 23, color: iconColor)),
           const SizedBox(width: 12),
         ],
         Expanded(child: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
-          Text(title, style: const TextStyle(fontSize: 15, color: Color(0xFF1A1A1A), fontWeight: FontWeight.w500)),
-          if (subtitle != null && subtitle!.isNotEmpty) Text(subtitle!, style: TextStyle(fontSize: 12, color: Colors.grey[500])),
+          Text(title, style: const TextStyle(fontSize: 18, color: Color(0xFF1A1A1A), fontWeight: FontWeight.w500)),
+          if (subtitle != null && subtitle!.isNotEmpty) Text(subtitle!, style: TextStyle(fontSize: 15, color: Colors.grey[500])),
         ])),
-        Switch(value: value, onChanged: onChanged, activeThumbColor: const Color(0xFF8B9CF7), activeTrackColor: const Color(0xFFC5BFFF)),
+        Switch(value: value, onChanged: onChanged, activeThumbColor: AppTheme.primary, activeTrackColor: const Color(0xFFC5BFFF)),
       ]),
     );
   }
@@ -210,7 +211,7 @@ class _TimeButton extends StatelessWidget {
     return GestureDetector(onTap: onTap, child: Container(
       padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 10),
       decoration: BoxDecoration(border: Border.all(color: const Color(0xFFE0E0E0)), borderRadius: BorderRadius.circular(10)),
-      child: Column(children: [Text(label, style: TextStyle(fontSize: 11, color: Colors.grey[500])), Text(time, style: const TextStyle(fontSize: 16, fontWeight: FontWeight.w600, color: Color(0xFF8B9CF7)))]),
+      child: Column(children: [Text(label, style: TextStyle(fontSize: 14, color: Colors.grey[500])), Text(time, style: const TextStyle(fontSize: 19, fontWeight: FontWeight.w600, color: AppTheme.primary))]),
     ));
   }
 }