/** Keep ASCII digits 0–9 only. */
export function digitsOnly(value: string): string {
  return value.replace(/\D/g, '');
}

/**
 * Letters (Unicode `\p{L}`) and whitespace only — strips digits, punctuation, symbols.
 */
export function lettersOnly(value: string): string {
  return value.replace(/[^\p{L}\s]/gu, '');
}