Tool results, denial comments and tool exception text now reach a span only
as a capture-gated preview; span.error is a fixed message, since it is
stored and exported regardless of content settings. A turn whose stream
yields an error event is recorded as failed. Search traces are listed by a
query copied into the small summary column, so the Logs timeline never
reads the spans JSONB. Adds GraphRAG span tests.
arc53-machine
efec1a2f83