request_review ignored artifacts entirely, so a review-bound card lost every
file its handoff named: the reviewer's complete_task is what runs
_cleanup_workspace over the managed scratch workspace.
Stage declared (explicit artifacts argument or metadata["artifacts"]) and
prose-referenced files into the task's durable attachments dir at the review
handoff, exactly as complete_task already does, carry the staged paths in the
review_requested event payload, and let the gateway notifier upload them (its
guard widens from completed to review_requested). ArtifactPreservationError
still rolls the whole transition back: the task stays running and retryable
with no attachments and no event.
yoyodine-industries