feat: add free email domains not blocked by HubSpot to validation list

### ✅ Summary This PR adds a curated list of disposable and free email domains **not currently blocked by HubSpot's built-in “Block free email” feature**. These domains are frequently used for spam, testing, or bypassing form restrictions, and should be explicitly blocked for better email hygiene and data quality. --- ### 📥 Domains Added | Domain | Service | |----------------------|--------------------| | sharklasers.com | Guerrilla Mail | | guerrillamail.com | Guerrilla Mail | | 10minutemail.com | 10 Minute Mail | | spambox.xyz | Spambox | | throwawaymail.com | ThrowAwayMail | | emailondeck.com | EmailOnDeck | | temp-mail.org | Temp-Mail | | tempmail.com | Temp-Mail | | tempmail.net | Temp-Mail | | tmails.net | Tmails | | mail.tm | Mail.tm | | 2mik.com | Misc (list repo) | | 3dboxer.com | Misc (list repo) | | hosliy.com | Misc (list repo) | | forcrack.com | Misc (list repo) | > **Note**: Sources for all domains are included in the linked CSV. --- ### 🧾 Why This Matters - 🧹 Improves **lead data quality** - 🧪 Reduces **test spam and junk registrations** - 🛡️ Enhances protection from temporary/disposable sign-ups - ❌ These are **not covered by HubSpot's default block list** ### 📚 Sources - [Guerrilla Mail](https://www.guerrillamail.com/) - [Temp-Mail](https://temp-mail.org/) - [ThrowAwayMail](https://www.throwawaymail.com/) - [GitHub: disposable-email-domains](https://github.com/disposable/disposable-email-domains)