This install is on external hosting and can't reach the central DB's private
LAN address (192.168.1.3), so the direct-DB burn always failed with
ECONNREFUSED. Redeem via the hub's api/sso_redeem.php over HTTPS (HMAC with
HUB_CONTENT_SECRET, ticket folded into the signature) and provision the
returned user into the local DB.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>