Phase 4.5: Completed responsive player layout and real username integration

frontend/lib/providers/auth_provider.dart

@@ -3,35 +3,42 @@ import 'package:shared_preferences/shared_preferences.dart';
 
 class AuthProvider with ChangeNotifier {
   String? _token;
+  String? _username; // 新增用户名状态
   bool _isAuthenticated = false;
 
   bool get isAuthenticated => _isAuthenticated;
   String? get token => _token;
+  String? get username => _username;
 
   AuthProvider() {
-    _loadToken();
+    _loadAuth();
   }
 
-  void _loadToken() async {
+  void _loadAuth() async {
     final prefs = await SharedPreferences.getInstance();
     _token = prefs.getString('token');
+    _username = prefs.getString('username');
     _isAuthenticated = _token != null;
     notifyListeners();
   }
 
-  Future<void> login(String token) async {
+  Future<void> login(String token, String username) async {
     _token = token;
+    _username = username;
     _isAuthenticated = true;
     final prefs = await SharedPreferences.getInstance();
     await prefs.setString('token', token);
+    await prefs.setString('username', username);
     notifyListeners();
   }
 
   Future<void> logout() async {
     _token = null;
+    _username = null;
     _isAuthenticated = false;
     final prefs = await SharedPreferences.getInstance();
     await prefs.remove('token');
+    await prefs.remove('username');
     notifyListeners();
   }
 }