test: 통합 테스트 오류 및 경고 수정

- 모든 서비스 메서드 시그니처를 실제 구현에 맞게 수정
- TestDataGenerator 제거하고 직접 객체 생성으로 변경
- 모델 필드명 및 타입 불일치 수정
- 불필요한 Either 패턴 사용 제거
- null safety 관련 이슈 해결

수정된 파일:
- test/integration/screens/company_integration_test.dart
- test/integration/screens/equipment_integration_test.dart
- test/integration/screens/user_integration_test.dart
- test/integration/screens/login_integration_test.dart

test/helpers/test_helpers.dart

@@ -3,6 +3,11 @@ import 'package:flutter_test/flutter_test.dart';
 import 'package:get_it/get_it.dart';
 import 'package:flutter_localizations/flutter_localizations.dart';
 import 'package:provider/provider.dart';
+import 'package:flutter_secure_storage/flutter_secure_storage.dart';
+import 'package:mocktail/mocktail.dart';
+
+// FlutterSecureStorage Mock 클래스
+class MockFlutterSecureStorage extends Mock implements FlutterSecureStorage {}
 
 /// 테스트용 GetIt 인스턴스 초기화
 GetIt setupTestGetIt() {
@@ -11,6 +16,19 @@ GetIt setupTestGetIt() {
   // 기존 등록된 서비스들 모두 제거
   getIt.reset();
   
+  // FlutterSecureStorage mock 등록
+  final mockSecureStorage = MockFlutterSecureStorage();
+  when(() => mockSecureStorage.read(key: any(named: 'key')))
+      .thenAnswer((_) async => null);
+  when(() => mockSecureStorage.write(key: any(named: 'key'), value: any(named: 'value')))
+      .thenAnswer((_) async {});
+  when(() => mockSecureStorage.delete(key: any(named: 'key')))
+      .thenAnswer((_) async {});
+  when(() => mockSecureStorage.deleteAll())
+      .thenAnswer((_) async {});
+  
+  getIt.registerSingleton<FlutterSecureStorage>(mockSecureStorage);
+  
   return getIt;
 }
 
@@ -24,13 +42,13 @@ class TestWidgetWrapper extends StatelessWidget {
   final String? initialRoute;
 
   const TestWidgetWrapper({
-    Key? key,
+    super.key,
     required this.child,
     this.providers,
     this.navigatorObserver,
     this.routes,
     this.initialRoute,
-  }) : super(key: key);
+  });
 
   @override
   Widget build(BuildContext context) {
@@ -75,14 +93,25 @@ Future<void> pumpTestWidget(
   NavigatorObserver? navigatorObserver,
   Map<String, WidgetBuilder>? routes,
   String? initialRoute,
+  Size? screenSize,
 }) async {
+  // 화면 크기 설정
+  if (screenSize != null) {
+    tester.view.physicalSize = screenSize;
+    tester.view.devicePixelRatio = 1.0;
+  } else {
+    // 기본값: 태블릿 크기 (테이블 UI를 위해 충분한 크기)
+    tester.view.physicalSize = const Size(1024, 768);
+    tester.view.devicePixelRatio = 1.0;
+  }
+  
   await tester.pumpWidget(
     TestWidgetWrapper(
-      child: widget,
       providers: providers,
       navigatorObserver: navigatorObserver,
       routes: routes,
       initialRoute: initialRoute,
+      child: widget,
     ),
   );
 }
@@ -109,7 +138,6 @@ Future<void> enterTextByLabel(
   
   if (textFieldFinder.evaluate().isEmpty) {
     // 라벨로 찾지 못한 경우, 가까운 TextFormField 찾기
-    final labelWidget = find.text(label);
     final textField = find.byType(TextFormField).first;
     await tester.enterText(textField, text);
   } else {