/**
 * Escape HTML special characters for safe insertion into the DOM.
 *
 * Accepts any value — null, undefined, and non-strings are coerced
 * to a string first (null/undefined become '').
 */
export function escapeHtml(value: unknown): string {
  if (value === null || value === undefined) return '';
  const str = typeof value === 'string' ? value : String(value);
  return str
    .replace(/&/g, '&')
    .replace(/</g, '&lt;')
    .replace(/>/g, '&gt;')
    .replace(/"/g, '&quot;');
}