Registration set no authenticatorSelection, so the browser offered the
passkey-manager 'save passkey' flow (Bitwarden) instead of prompting for the
YubiKey. Now request a cross-platform, non-resident, presence-only credential:
authenticatorAttachment=cross-platform (roaming key, not a platform/manager
passkey), residentKey=discouraged (non-discoverable second factor — what keeps
passkey managers out), userVerification=discouraged (single touch, no PIN).
Login assertion also uses discouraged so it is: insert key, one tap, done.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
WebauthnService builds creation/request options (rpId = active domain, ES256/RS256,
attestation none, exclude/allow lists) via web-auth/webauthn-lib v5, stores the
challenge in the session, and verifies attestation/assertion responses (allowed
origin = https://<rpId>, sign-count tracked). Option building + serialization are
unit-tested; the cryptographic verify path is browser-verified on a domain host.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
boban