The credential-delivery mechanism changed during execution: the host now
passes resolved {base_url, api_key} in PollChangesRequest.connection each
poll (not plugin runtime config). Also records source auto-discovery,
nullable connection_id, and the per-source interval floor decided at the
final integration review.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>