An error redirect carrying the expected state nonce comes from the genuine
authorization flow (e.g. the user denied the consent screen); leaving it
unsettled stalled loopback logins for the full 5-minute timeout. Reject the
callback promise for those, while still ignoring forgeable errors without
the expected state (#4106).
Kept the callback promise pending after malformed, denied, or state-mismatched requests so a legitimate browser redirect can still complete login.
Bound localhost callback servers explicitly to 127.0.0.1 instead of Bun's all-interface default.
Fixes#4106