Implement Multi-Factor Authentication (MFA) using an Authenticator app (e.g., Google Authenticator, Microsoft Authenticator) to enhance the security of user accounts by requiring a second form of verification in addition to the traditional username and password. MFA should be optional for the user. Changes: https://github.com/achromaticlabs/pro/commit/d712259c174cc6f7ebacf5f7a7a4ef4afc32f5fe