// Replace GPT-generated direct ASIN links with safer search links
$reply = preg_replace_callback('/https?:\/\/www\.amazon\.com\/dp\/([A-Z0-9]{10})/i', function($matches) {
  $asin = $matches[1];
  return 'https://www.amazon.com/s?k=' . $asin . '&tag=' . ATSP_AFFIL_TAG;
}, $reply);