# Enable Two-Factor Authentication

**ID:** EU-004
**Priority:** High
**Status:** Planned

## User Story
As an end user, I want to enable two-factor authentication on my account so that my account is protected even if my password is compromised.

## Acceptance Criteria
- [ ] User can enable 2FA from account settings
- [ ] Support for TOTP apps (Google Authenticator, Authy, etc.)
- [ ] Backup codes are generated and shown once during setup
- [ ] User must verify 2FA code during setup to confirm it works
- [ ] Login flow prompts for 2FA code when enabled
- [ ] User can disable 2FA (requires current 2FA code)
- [ ] Account recovery option if 2FA device is lost

## Technical Notes
- Mobile verification infrastructure exists (SMS OTP in registration)
- Can leverage existing `smarttwilio` integration for SMS-based 2FA
- TOTP implementation needs `otplib` or similar library
- Store encrypted TOTP secret in User model
- Consider supporting multiple 2FA methods (TOTP, SMS, security keys)

## Related TODOs
- New feature - no existing TODO
