Descrizione
Verifica la deliverability di un'email via DNS MX lookup (RFC 5321 fallback A record incluso). Detect domini disposable (mailinator, tempmail, ecc. — 250+ blacklist). Detect role-based vs person email (info@ vs nome.cognome@). Output: confidence 0-100. Cache LRU 5min × 5000 domini → trascurabile in batch.
