결재 API 계약 보완 및 테스트 정리

test/features/approvals/approval_page_permission_test.dart

@@ -245,7 +245,7 @@ class _StubApprovalRepository implements ApprovalRepository {
   }
 
   @override
-  Future<Approval> create(ApprovalInput input) {
+  Future<Approval> create(ApprovalCreateInput input) {
     throw UnimplementedError();
   }
 
@@ -260,7 +260,7 @@ class _StubApprovalRepository implements ApprovalRepository {
   }
 
   @override
-  Future<Approval> update(int id, ApprovalInput input) {
+  Future<Approval> update(ApprovalUpdateInput input) {
     throw UnimplementedError();
   }
 }