feat: 健康录入提醒 + 多指标异常 + 用药漏服 + UI 优化

后端
- NotificationPreference 增加健康录入提醒总开关和 5 子项（血压/心率/血糖/血氧/体重）
- EF 迁移 AddHealthRecordReminder
- 新增 GET/PUT /api/notification-prefs
- 新增 HealthRecordReminderService 每天 9 点/12 点扫描未录入用户推送提醒

前端
- 通知偏好对接真实后端 API
- 设置页新增「健康录入提醒」总开关+5 子项
- 通知中心右上角加齿轮跳设置页
- 今日健康卡片：4 项异常检测+多项合并；用药只显漏服并按时间窗口区分文案
- 侧边栏头像改圆形白底灰图标，去掉紫色品牌渐变
- 整体背景统一浅灰白 #F6F8FC，去掉浅紫渐变
- 设置页简化（去掉分组/彩色图标方块）
- 健康档案保存按钮移到右上角，TextButton 全局默认黑色
- API baseUrl 跟随网络环境

health_app/lib/widgets/health_drawer.dart

@@ -68,28 +68,25 @@ class _AccountHeader extends StatelessWidget {
       children: [
         InkWell(
           onTap: () => pushRoute(ref, 'profile'),
-          borderRadius: BorderRadius.circular(24),
+          borderRadius: BorderRadius.circular(33),
           child: Container(
             width: 66,
             height: 66,
             decoration: BoxDecoration(
-              gradient: const LinearGradient(
-                begin: Alignment.topLeft,
-                end: Alignment.bottomRight,
-                colors: [Color(0xFFA5F3FC), Color(0xFFD8B4FE)],
-              ),
-              borderRadius: BorderRadius.circular(24),
+              color: Colors.white,
+              shape: BoxShape.circle,
+              border: Border.all(color: const Color(0xFFE9EEF5)),
               boxShadow: [
                 BoxShadow(
-                  color: const Color(0xFF7C3AED).withValues(alpha: 0.12),
-                  blurRadius: 22,
-                  offset: const Offset(0, 12),
+                  color: const Color(0xFF101828).withValues(alpha: 0.06),
+                  blurRadius: 14,
+                  offset: const Offset(0, 6),
                 ),
               ],
             ),
             child: const Icon(
               Icons.person_rounded,
-              color: Colors.white,
+              color: Color(0xFF94A3B8),
               size: 34,
             ),
           ),
@@ -357,9 +354,9 @@ class _NavigationSection extends StatelessWidget {
     return _Panel(
       title: '功能入口',
       backgroundGradient: const LinearGradient(
-        begin: Alignment.bottomCenter,
-        end: Alignment.topCenter,
-        colors: [Color(0xFFA8EDEA), Color(0xFFFED6E3)],
+        begin: Alignment.topCenter,
+        end: Alignment.bottomCenter,
+        colors: [Color(0xFFEAF4FB), Color(0xFFF4F9FD)],
       ),
       child: GridView.builder(
         itemCount: items.length,