feat: introduce TaxForm entity and adapter, refactor tax forms repository and use cases for improved data handling

apps/mobile/packages/domain/lib/src/entities/profile/tax_form.dart

@@ -0,0 +1,45 @@
+import 'package:equatable/equatable.dart';
+
+enum TaxFormType { i9, w4 }
+
+enum TaxFormStatus { notStarted, inProgress, submitted, approved, rejected }
+
+class TaxForm extends Equatable {
+  final String id;
+  final TaxFormType type;
+  final String title;
+  final String? subtitle;
+  final String? description;
+  final TaxFormStatus status;
+  final String? staffId;
+  final Map<String, dynamic>? formData;
+  final DateTime? createdAt;
+  final DateTime? updatedAt;
+
+  const TaxForm({
+    required this.id,
+    required this.type,
+    required this.title,
+    this.subtitle,
+    this.description,
+    this.status = TaxFormStatus.notStarted,
+    this.staffId,
+    this.formData,
+    this.createdAt,
+    this.updatedAt,
+  });
+
+  @override
+  List<Object?> get props => [
+        id,
+        type,
+        title,
+        subtitle,
+        description,
+        status,
+        staffId,
+        formData,
+        createdAt,
+        updatedAt,
+      ];
+}