## Why
`codex exec` recovers turn items at completion because item notifications can be dropped under backpressure. This recovery needs to respect the thread's history mode.
## What changed
For paginated threads, fetch every page from `thread/items/list`, scoped to the completed turn. Preserve items already present in the completion notification when merging the recovered history, and stop recovery if a cursor repeats. Keep `thread/read` recovery for other history modes.
## Testing
Add regression coverage for recovering a final answer across multiple item pages and for a failed fork recovering only its own turn.
GitOrigin-RevId: f005ca2cf9d8313bbbf32ed4c228ebb5e51428a2
## Why
Multi-agent exec sessions can receive child `turn/completed` notifications on
the same event stream as the primary turn. Backfilling those unrelated
completions issues unnecessary `thread/read` requests.
## What changed
Run completion-item backfill only after a notification has been matched to the
primary exec thread and turn.
## Testing
Add an integration test that delivers a child completion before the primary
completion and verifies that only the primary completion triggers backfill.
GitOrigin-RevId: 46a41236ee6a39e4b341570ff4826a71fa02bb32
Brent Traut