修复用户端个人头像展示

apps/user_app/lib/data/services/api_client.dart

@@ -1,6 +1,7 @@
 // 功能描述：封装用户端 HTTP 请求，并将服务端错误转换为安全、可读的中文提示。
 // 版本：1.1.0
 import 'dart:convert';
+import 'dart:typed_data';
 
 import 'package:http/http.dart' as http;
 
@@ -104,6 +105,20 @@ class ApiClient {
   Future<Object?> get(String path, {bool authenticated = true}) =>
       _send('GET', path, authenticated: authenticated);
 
+  /// 读取需要鉴权的二进制资源；资源不存在时返回空值。
+  Future<Uint8List?> getBytes(String path) async {
+    final request = http.Request('GET', Uri.parse('$baseUrl$path'));
+    request.headers['accept'] = 'image/jpeg, image/png';
+    final token = _tokenProvider();
+    if (token.isNotEmpty) request.headers['authorization'] = token;
+    final response = await _sendRequest(request);
+    if (response.statusCode == 404) return null;
+    if (response.statusCode < 200 || response.statusCode >= 300) {
+      throw ApiException(response.statusCode, '头像加载失败');
+    }
+    return response.bodyBytes.isEmpty ? null : response.bodyBytes;
+  }
+
   Future<Object?> post(
     String path, {
     Map<String, Object?>? body,