Four fixes for the MFA sign-in flow:
1. Fix passkey verify crash: extract authenticationOptions from Logto
response (was passing full response as optionsJSON). Pass
verificationId to the verify endpoint.
2. Default to passkey verification when no MFA method preference is
stored (was showing method picker which offered TOTP to passkey-only
users).
3. Show backup codes after MFA enrollment: new mfaEnrollBackupCodes
mode with copy/download buttons and confirmation checkbox. Users
must save codes before completing sign-in.
4. Remove duplicate error alerts in enrollment screens (top-level
alert handles all modes).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
0481cefaf4