v1.4.43 W13 L-3 — `verifyAuthentication` parsed the inbound JSON
body via a raw `as AuthenticationResponseJSON` cast straight into
`verifyAuthenticationResponse`. The SimpleWebAuthn verifier owned
cryptographic validation downstream, but the cast bypassed TS's
type-narrowing — a future refactor reading `typedResponse.id`
before calling the verifier would have crashed on `undefined.id`.
Drop the cast, parse via a Zod schema that mirrors
SimpleWebAuthn's `AuthenticationResponseJSON` shape (id, rawId,
nested response with clientDataJSON / authenticatorData /
signature, type literal "public-key"). Permissive on unknown
top-level keys for forward-compatibility with future
authenticator-attachment / extension-result additions; the strict
cryptographic checks remain inside the verifier.
A malformed body now throws here with a structured
"Malformed passkey authentication response" error before any
deref, closing the boundary gap.
