feat: add payment card grouping and analysis

lib/models/payment_card_model.dart

@@ -0,0 +1,33 @@
+import 'package:hive/hive.dart';
+
+part 'payment_card_model.g.dart';
+
+@HiveType(typeId: 2)
+class PaymentCardModel extends HiveObject {
+  @HiveField(0)
+  String id;
+
+  @HiveField(1)
+  String issuerName;
+
+  @HiveField(2)
+  String last4;
+
+  @HiveField(3)
+  String colorHex;
+
+  @HiveField(4)
+  String iconName;
+
+  @HiveField(5)
+  bool isDefault;
+
+  PaymentCardModel({
+    required this.id,
+    required this.issuerName,
+    required this.last4,
+    required this.colorHex,
+    required this.iconName,
+    this.isDefault = false,
+  });
+}