Root cause of the permanent stuck-at-challenge symptom: a stale
appAttestKeyId in Keychain (Secure Enclave key invalidated by an app
reinstall or signing change) makes generateAssertion fail every time
with DCError code 2 (invalidInput). Only NetworkError 403 was clearing
the stored key, so this local rejection was never recovered from -
every guest-authed call kept retrying the same broken key forever.
Catch DCError here too and fall through to fresh attestation.
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.
