Both dashboard-auth JWT verification paths (self-hosted OIDC ID token and the
Nous Portal access token, via the shared verify_jwt) called PyJWT jwt.decode
with the default leeway=0 while requiring iat. Any host whose clock lags the
issuer's — unsynced containers/VMs, NTP jitter — failed login with
ImmatureSignatureError, and the failure was folded into ProviderError, i.e.
HTTP 503 'provider unreachable', discarding already-rotated refresh tokens
and forcing unrecoverable re-logins.
- verify_jwt gains leeway (default 60s, RFC 7519 §4.1.4-4.1.6) and classifies
ImmatureSignatureError as InvalidCodeError (validation failure -> 401 /
refresh) instead of ProviderError/503.
- New parse_leeway helper: fail-closed parsing (unparseable / negative / NaN /
inf -> 0, never widens the window); 0 honours strict mode.
- Self-hosted OIDC: id_token_leeway kwarg + dashboard.oauth.self_hosted.id_token_leeway.
- Nous: token_leeway kwarg + dashboard.oauth.token_leeway.
- No new env vars (config.yaml-only knobs).
Fixes#47815
c5cb0f597b