The catch filter only matched DomainException/OperationCanceledException,
so anything else escaped a hosted service and took the host down. One such
path was mine: `"items": null` deserializes over the property initialiser,
so `data.Items.Select(...)` would NullReferenceException straight past the
filter.
Fixed at both ends - the reader tolerates a null or absent items array, and
the catch is now a deliberate catch-all that only lets a genuine host
shutdown through. This is a diagnostic; a diagnostic that can core-dump the
thing it diagnoses is worse than no diagnostic at all.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>