Add passkey registration and sign-in without leaving Expo.

import {
  authenticateWithPasskey,
  createPasskey,
  getPasskeyAvailability,
} from "expo-easy-passkey";

const availability = getPasskeyAvailability();

if (availability.supported) {
  const options = await fetchRegistrationOptions();
  const credential = await createPasskey(options);
  await verifyRegistration(credential);

  const request = await fetchAuthenticationOptions();
  const assertion = await authenticateWithPasskey(request);
  await verifyAuthentication(assertion);
}