Testing surfaced two problems with the per-thread fan-out:
1. Authorization (blocker): CreateComment rejected any agent comment on the
task's issue whose parent_id != task.TriggerCommentID, so replies to the
OTHER coalesced threads were denied ('parent_id must equal this task's
trigger comment id') and those threads never got a reply. Allow the trigger
comment OR any comment the task coalesced (taskCoversReplyParent: trigger ∪
coalesced_comment_ids); every other parent on the issue is still rejected,
so this stays scoped to the set the run was actually given to answer.
2. Ordering: the agent answered the newest (triggering) comment first. The
fan-out instruction now numbers the targets and explicitly requires posting
OLDEST thread first, the newest/triggering thread last, so replies land in
chronological order. commentReplyThreads already lists oldest-first.
Tests: TestTaskCoversReplyParent (allow-list) and chronological-order
assertions in the cross-thread prompt test.
Co-authored-by: Eve <eve@multica-ai.local>
Co-authored-by: multica-agent <github@multica.ai>
