Guest session handshake fails silently after the challenge step - no
console output, just a generic "could not load" message in the UI.
DCAppAttestService errors (generateKey/attestKey/generateAssertion)
propagate up uncaught by anything that logs them. Add explicit logging
at each step so the real thrown error is visible instead of debugging
blind.
Adds a pre-login public store locator (guest session via DeviceCheck/App
Attest, keychain-backed token storage) so the app no longer forces sign-in
before showing any content, plus updated support URL metadata.