feat: 应用内通知系统 + 结构化手术史/用药等相关改动

- 新增用户通知 outbox 流水线(EfUserNotificationPipeline)与后台投递 worker
- 通知中心页面及前端通知服务接入
- 健康指标异常、用药/运动提醒等事件统一产出站内通知
- 健康档案结构化手术史、用药提醒扫描、医生/用户端点等配套调整
- AppDbContext 注册通知相关实体

health_app/lib/core/api_client.dart

@@ -3,8 +3,21 @@ import 'dart:io';
 import 'package:dio/dio.dart';
 import 'local_database.dart';
 
-/// API 基础地址
-const String baseUrl = 'http://localhost:5000';  // adb reverse 或同WiFi直连时改为PC的IP
+/// API 基础地址。可通过 --dart-define=API_BASE_URL=http://host:5000 覆盖。
+const String baseUrl = String.fromEnvironment(
+  'API_BASE_URL',
+  defaultValue: 'http://localhost:5000',
+);
+
+class ApiException implements Exception {
+  final int? code;
+  final String message;
+
+  const ApiException(this.message, {this.code});
+
+  @override
+  String toString() => message;
+}
 
 /// Dio HTTP 客户端封装——带 token 注入、401 自动刷新
 class ApiClient {
@@ -40,22 +53,22 @@ class ApiClient {
 
   /// 带 token 的 GET 请求
   Future<Response> get(String path, {Map<String, dynamic>? queryParameters}) async {
-    return _dio.get(path, queryParameters: queryParameters);
+    return _request(_dio.get(path, queryParameters: queryParameters));
   }
 
   /// 带 token 的 POST 请求
   Future<Response> post(String path, {dynamic data}) async {
-    return _dio.post(path, data: data);
+    return _request(_dio.post(path, data: data));
   }
 
   /// 带 token 的 PUT 请求
   Future<Response> put(String path, {dynamic data}) async {
-    return _dio.put(path, data: data);
+    return _request(_dio.put(path, data: data));
   }
 
   /// 带 token 的 DELETE 请求
   Future<Response> delete(String path) async {
-    return _dio.delete(path);
+    return _request(_dio.delete(path));
   }
 
   /// 上传文件（multipart），返回文件 URL
@@ -63,7 +76,7 @@ class ApiClient {
     final formData = FormData.fromMap({
       fieldName: await MultipartFile.fromFile(file.path, filename: file.path.split('/').last),
     });
-    final res = await _dio.post(path, data: formData);
+    final res = await _request(_dio.post(path, data: formData));
     final data = res.data;
     if (data is Map) {
       final topUrl = data['url']?.toString();
@@ -82,6 +95,46 @@ class ApiClient {
     }
     return null;
   }
+
+  Response _ensureBusinessSuccess(Response response) {
+    final body = response.data;
+    if (body is Map && body.containsKey('code')) {
+      final rawCode = body['code'];
+      final code = rawCode is int ? rawCode : int.tryParse('$rawCode');
+      if (code != null && code != 0) {
+        throw ApiException(
+          body['message']?.toString().trim().isNotEmpty == true
+              ? body['message'].toString()
+              : '请求失败',
+          code: code,
+        );
+      }
+    }
+    return response;
+  }
+
+  Future<Response> _request(Future<Response> request) async {
+    try {
+      return _ensureBusinessSuccess(await request);
+    } on DioException catch (error) {
+      final body = error.response?.data;
+      final message = body is Map && body['message']?.toString().trim().isNotEmpty == true
+          ? body['message'].toString()
+          : error.type == DioExceptionType.connectionTimeout ||
+                  error.type == DioExceptionType.receiveTimeout
+              ? '请求超时，请稍后重试'
+              : error.type == DioExceptionType.connectionError
+                  ? '无法连接服务器，请检查网络或后端地址'
+                  : '请求失败，请稍后重试';
+      final rawCode = body is Map ? body['code'] : null;
+      throw ApiException(
+        message,
+        code: rawCode is int
+            ? rawCode
+            : int.tryParse('$rawCode') ?? error.response?.statusCode,
+      );
+    }
+  }
 }
 
 /// 认证拦截器：自动注入 token + 401 刷新

health_app/lib/core/app_router.dart

@@ -12,6 +12,7 @@ import '../pages/report/ai_analysis_page.dart';
 import '../pages/consultation/consultation_pages.dart';
 import '../pages/settings/settings_pages.dart';
 import '../pages/settings/notification_prefs_page.dart';
+import '../pages/notifications/notification_center_page.dart';
 import '../pages/profile/profile_page.dart';
 import '../pages/diet/diet_capture_page.dart';
 import '../pages/device/device_scan_page.dart';
@@ -97,6 +98,8 @@ Widget buildPage(RouteInfo route, WidgetRef ref) {
       return const SettingsPage();
     case 'notificationPrefs':
       return const NotificationPrefsPage();
+    case 'notifications':
+      return const NotificationCenterPage();
     case 'staticText':
       return StaticTextPage(type: params['type']!);
     case 'dietDetail':