- Add <?= \$head ?? '' ?> after _theme include in all five admin views
  (conflicts/index, conflicts/show, settings/index, users/index, users/edit)
  so Config\Sync::\$headView is actually rendered for host apps that set it
- users/edit.php: rename .modal-backdrop/.modal/.close to
  .twofa-backdrop/.sync-modal/.close-btn (matches users/index.php and
  avoids conflict with Bootstrap 5 classes if Bootstrap is ever loaded here)
- Delete src/Views/users/_row.php (dead file, superseded by DTE AJAX)