refactor(support): consolidate remaining ID normalization via toIntIds()

Extends the toIntIds() rollout to service and repository layers:

- Drops a third private duplicate (UserCustomFieldValueService::normalizeTenantIds)
- Collapses the two-line intval+filter pattern inside UserAssignmentService,
  UserAuthorizationPolicy, SsoUserLinkService, DepartmentService, and
  UserCustomFieldValueService
- Replaces inline patterns in 4 repositories (RolePermissionRepository,
  RoleAssignableRoleRepository, UserWriteRepository, DepartmentRepository,
  UserCustomFieldValueRepository, UserCustomFieldValueOptionRepository)
- Simplifies the notifications sanitizeTenantIds trait body

Tenant-area files deliberately untouched per parallel ongoing work on
the tenant-logo refactor.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

modules/notifications/lib/Module/Notifications/Listeners/NotificationListenerTrait.php

@@ -46,11 +46,6 @@ trait NotificationListenerTrait
      */
     protected function sanitizeTenantIds(mixed $tenantIds): array
     {
-        if (!is_array($tenantIds)) {
-            return [];
-        }
-
-        $ids = array_values(array_unique(array_map('intval', $tenantIds)));
-        return array_values(array_filter($ids, static fn (int $tenantId): bool => $tenantId > 0));
+        return is_array($tenantIds) ? toIntIds($tenantIds) : [];
     }
 }