feat: 用药提醒功能 + 移除医生相关页面

- 后端新增 GET /api/medications/reminders 接口
- 前端任务卡片区显示真实用药提醒
- 移除 DoctorListPage/DoctorChatPage 路由
- 移除"找医生"面板按钮
- 医生端另做 Web 页面

health_app/lib/providers/data_providers.dart

@@ -45,6 +45,11 @@ final medicationListProvider = FutureProvider<List<Map<String, dynamic>>>((ref)
   return service.getList();
 });
 
+final medicationReminderProvider = FutureProvider<List<Map<String, dynamic>>>((ref) async {
+  final service = ref.watch(medicationServiceProvider);
+  return service.getReminders();
+});
+
 /// 医生列表 Provider
 final doctorListProvider = FutureProvider<List<Map<String, dynamic>>>((ref) async {
   final service = ref.watch(consultationServiceProvider);