전역 구조 리팩터링 및 테스트 확장

lib/features/approvals/domain/entities/approval.dart

@@ -211,19 +211,13 @@ class ApprovalStepActionInput {
 
 /// 결재 단계를 일괄 등록/재배치하기 위한 입력 모델
 class ApprovalStepAssignmentInput {
-  ApprovalStepAssignmentInput({
-    required this.approvalId,
-    required this.steps,
-  });
+  ApprovalStepAssignmentInput({required this.approvalId, required this.steps});
 
   final int approvalId;
   final List<ApprovalStepAssignmentItem> steps;
 
   Map<String, dynamic> toPayload() {
-    return {
-      'id': approvalId,
-      'steps': steps.map((e) => e.toJson()).toList(),
-    };
+    return {'id': approvalId, 'steps': steps.map((e) => e.toJson()).toList()};
   }
 }