/** Copy text to clipboard with execCommand fallback for older browsers. */
export function copyToClipboard(text: string, onSuccess: () => void): void {
  if (navigator.clipboard?.writeText) {
    navigator.clipboard.writeText(text).then(onSuccess);
  } else {
    const ta = document.createElement('textarea');
    ta.value = text;
    ta.style.position = 'fixed';
    ta.style.opacity = '0';
    document.body.appendChild(ta);
    ta.select();
    document.execCommand('copy');
    document.body.removeChild(ta);
    onSuccess();
  }
}