Initial commit: QR Scanner Flutter app

App móvil para validar pases QR contra base-admin-web con login Cognito,
escáner en tiempo real, feedback auditivo/háptico y README completo.

lib/models/scan_response.dart

@@ -0,0 +1,23 @@
+import 'package:qrscanner/models/pass_code.dart';
+
+class ScanResponse {
+  const ScanResponse({
+    required this.success,
+    this.message,
+    this.passCode,
+  });
+
+  factory ScanResponse.fromJson(Map<String, dynamic> json) {
+    return ScanResponse(
+      success: json['success'] == true,
+      message: json['message'] as String?,
+      passCode: json['passCode'] is Map<String, dynamic>
+          ? PassCode.fromJson(json['passCode'] as Map<String, dynamic>)
+          : null,
+    );
+  }
+
+  final bool success;
+  final String? message;
+  final PassCode? passCode;
+}