chore(inventory): 리스트 수정 단추를 세부 액션으로 한정

- 입고·출고·대여 페이지 상단의 "선택 항목 수정" 버튼을 제거하고 상세 패널 내 수정 흐름만 노출\n- 제품 상세 다이얼로그에서 준비 중인 히스토리 섹션과 상수 정의를 제거해 UI를 단순화\n- 관련 위젯 테스트에서 히스토리 탭 검증을 삭제하고 문구를 최신 설명으로 갱신

lib/features/inventory/inbound/presentation/pages/inbound_page.dart

@@ -336,17 +336,6 @@ class _InboundPageState extends State<InboundPage> {
             child: const Text('입고 등록'),
           ),
         ),
-        PermissionGate(
-          resource: PermissionResources.stockTransactions,
-          action: PermissionAction.edit,
-          child: ShadButton.outline(
-            leading: const Icon(lucide.LucideIcons.pencil, size: 16),
-            onPressed: _selectedRecord == null
-                ? null
-                : () => _handleEdit(_selectedRecord!),
-            child: const Text('선택 항목 수정'),
-          ),
-        ),
       ],
       toolbar: FilterBar(
         actionConfig: FilterBarActionConfig(

lib/features/inventory/outbound/presentation/pages/outbound_page.dart

@@ -423,17 +423,6 @@ class _OutboundPageState extends State<OutboundPage> {
             child: const Text('출고 등록'),
           ),
         ),
-        PermissionGate(
-          resource: PermissionResources.stockTransactions,
-          action: PermissionAction.edit,
-          child: ShadButton.outline(
-            leading: const Icon(lucide.LucideIcons.pencil, size: 16),
-            onPressed: _selectedRecord == null
-                ? null
-                : () => _handleEdit(_selectedRecord!),
-            child: const Text('선택 항목 수정'),
-          ),
-        ),
       ],
       toolbar: FilterBar(
         actionConfig: FilterBarActionConfig(

lib/features/inventory/rental/presentation/pages/rental_page.dart

@@ -369,17 +369,6 @@ class _RentalPageState extends State<RentalPage> {
             child: const Text('대여 등록'),
           ),
         ),
-        PermissionGate(
-          resource: PermissionResources.stockTransactions,
-          action: PermissionAction.edit,
-          child: ShadButton.outline(
-            leading: const Icon(lucide.LucideIcons.pencil, size: 16),
-            onPressed: _selectedRecord == null
-                ? null
-                : () => _handleEdit(_selectedRecord!),
-            child: const Text('선택 항목 수정'),
-          ),
-        ),
       ],
       toolbar: FilterBar(
         actionConfig: FilterBarActionConfig(