create promocode page

lib/data/models/promo_code_response_dto.dart

@@ -0,0 +1,25 @@
+import '../../domain/entities/promo_code_result.dart';
+
+class PromoCodeResponseDto {
+  final bool success;
+  final double balance;
+
+  PromoCodeResponseDto({
+    required this.success,
+    required this.balance,
+  });
+
+  factory PromoCodeResponseDto.fromJson(Map<String, dynamic> json) {
+    return PromoCodeResponseDto(
+      success: json['success'] as bool,
+      balance: (json['balance'] as num).toDouble(),
+    );
+  }
+
+  PromoCodeResult toEntity() {
+    return PromoCodeResult(
+      success: success,
+      balance: balance,
+    );
+  }
+}