feat: 后端架构重构 — Endpoint→Service→Repository分层 + AI确认机制 + 异步任务持久化

- 核心业务拆分为 Endpoint → Application Service → Repository 三层
- AI写入操作必须用户确认后才写库(确认卡片机制)
- 报告/饮食/用药分析改为持久化任务队列(原子领取/重试/重启恢复)
- 运动计划修复: 连续真实日期替代周模板
- 用药提醒去重 + 通知Outbox预留
- 认证收拢到AuthService, 管理员收拢到AdminService
- AI会话加用户归属校验防串号
- 提示词调整为患者视角
- 开发假数据已关闭
- 21/21测试通过, 0警告0错误

health_app/lib/services/in_app_notification_service.dart

@@ -0,0 +1,43 @@
+import '../core/api_client.dart';
+
+class InAppNotification {
+  final String id;
+  final String type;
+  final String title;
+  final String message;
+
+  const InAppNotification({
+    required this.id,
+    required this.type,
+    required this.title,
+    required this.message,
+  });
+
+  factory InAppNotification.fromJson(Map<String, dynamic> json) =>
+      InAppNotification(
+        id: json['id']?.toString() ?? '',
+        type: json['type']?.toString() ?? '',
+        title: json['title']?.toString() ?? '健康提醒',
+        message: json['message']?.toString() ?? '',
+      );
+}
+
+class InAppNotificationService {
+  final ApiClient _api;
+
+  const InAppNotificationService(this._api);
+
+  Future<List<InAppNotification>> getPending() async {
+    final response = await _api.get('/api/notifications/pending');
+    final items = response.data['data'] as List? ?? const [];
+    return items
+        .whereType<Map>()
+        .map((item) => InAppNotification.fromJson(Map<String, dynamic>.from(item)))
+        .where((item) => item.id.isNotEmpty)
+        .toList();
+  }
+
+  Future<void> acknowledge(String id) async {
+    await _api.post('/api/notifications/$id/acknowledge');
+  }
+}