feat: 결재·마스터 실연동 업데이트

lib/features/util/postal_search/presentation/widgets/postal_search_dialog.dart

@@ -2,6 +2,7 @@ import 'package:flutter/material.dart';
 import 'package:get_it/get_it.dart';
 import 'package:shadcn_ui/shadcn_ui.dart';
 
+import 'package:superport_v2/core/network/failure.dart';
 import 'package:superport_v2/widgets/components/superport_table.dart';
 
 import '../../domain/entities/postal_code.dart';
@@ -102,7 +103,8 @@ class _PostalSearchDialogState extends State<_PostalSearchDialog> {
       if (!mounted) return;
       setState(() {
         _results = const [];
-        _errorMessage = error.toString();
+        final failure = Failure.from(error);
+        _errorMessage = failure.describe();
       });
     } finally {
       if (mounted) {