Add initial project structure and configuration files for iOS and Android

lib/features/auth/models/auth_credentials.dart

@@ -0,0 +1,11 @@
+class AuthCredentials {
+  final String username;
+  final String password;
+
+  AuthCredentials({required this.username, required this.password});
+
+  Map<String, dynamic> toJson() => {
+        'username': username,
+        'password': password,
+      };
+}

lib/features/auth/models/auth_token.dart

@@ -0,0 +1,26 @@
+import 'package:equatable/equatable.dart';
+
+class AuthToken extends Equatable {
+  final String accessToken;
+  final String refreshToken;
+  final DateTime expiresAt;
+  
+  const AuthToken({
+    required this.accessToken,
+    required this.refreshToken,
+    required this.expiresAt,
+  });
+  
+  factory AuthToken.fromJson(Map<String, dynamic> json) {
+    return AuthToken(
+      accessToken: json['access_token'],
+      refreshToken: json['refresh_token'],
+      expiresAt: DateTime.parse(json['expires_at']),
+    );
+  }
+  
+  bool get isExpired => DateTime.now().isAfter(expiresAt);
+  
+  @override
+  List<Object> get props => [accessToken, refreshToken, expiresAt];
+}