feat(proj): init

mobile/lib/data/models/auth_user.dart

@@ -0,0 +1,79 @@
+import 'dart:convert';
+
+import 'package:please_pay_me/data/models/json.dart';
+
+class AuthUser {
+  const AuthUser({
+    required this.userId,
+    this.firstName,
+    this.lastName,
+    this.username,
+    this.photoUrl,
+  });
+
+  factory AuthUser.fromJson(Map<String, dynamic> json) {
+    return AuthUser(
+      userId: asInt(json['user_id']),
+      firstName: asStringOrNull(json['first_name']),
+      lastName: asStringOrNull(json['last_name']),
+      username: asStringOrNull(json['username']),
+      photoUrl: asStringOrNull(json['photo_url']),
+    );
+  }
+
+  static AuthUser? tryDecode(String? raw) {
+    if (raw == null || raw.isEmpty) return null;
+    try {
+      return AuthUser.fromJson(asMap(jsonDecode(raw)));
+    } on FormatException {
+      return null;
+    }
+  }
+
+  final int userId;
+  final String? firstName;
+  final String? lastName;
+  final String? username;
+  final String? photoUrl;
+
+  String get displayName {
+    final full = [firstName, lastName].whereType<String>().join(' ').trim();
+    if (full.isNotEmpty) return full;
+    if (username != null) return '@$username';
+    return 'Пользователь $userId';
+  }
+
+  String get handle => username != null ? '@$username' : 'id $userId';
+
+  String get initials {
+    final source = firstName?.trim().isNotEmpty == true
+        ? firstName!.trim()
+        : username?.trim() ?? '';
+    if (source.isEmpty) return '';
+    return source.substring(0, 1);
+  }
+
+  Map<String, dynamic> toJson() => {
+        'user_id': userId,
+        'first_name': firstName,
+        'last_name': lastName,
+        'username': username,
+        'photo_url': photoUrl,
+      };
+
+  String encode() => jsonEncode(toJson());
+}
+
+class AuthSession {
+  const AuthSession({required this.accessToken, required this.user});
+
+  factory AuthSession.fromJson(Map<String, dynamic> json) {
+    return AuthSession(
+      accessToken: asString(json['access_token']),
+      user: AuthUser.fromJson(asMap(json['user'])),
+    );
+  }
+
+  final String accessToken;
+  final AuthUser user;
+}