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,
+      };
+}