## What changed
- Add the zero-based `window_number` to Responses turn metadata and include it in prewarm requests.
- Persist `forked_from_ordinal_exclusive` separately from the physical history base so fork lineage remains accurate after reverts and cold resumes.
- Report context-inheriting subagents through `parent_thread_id` without also emitting fork lineage.
- Reserve the new metadata keys while accepting and filtering previously valid configured values so Codex-owned values take precedence.
## Testing
- Cover window numbering across compaction, resume, and fork operations.
- Cover fork cutoff persistence across direct forks, legacy rollouts, reverts into inherited history, and cold resumes.
GitOrigin-RevId: 288f6cd632254814c1f166668b33828082d799a1
## What changed
- Add the experimental `thread/revert` request, which replaces a loaded paginated thread's durable history with the prefix before `beforeTurnId` while preserving the thread ID.
- Interrupt any active turn, reload the replacement history without unloading the thread, preserve mutable thread settings, and emit `thread/reverted`.
- Return backward pagination cursors for the retained turns and items, reject stale rollout paths after a revert, and document that local file changes are unaffected.
## Testing
- Cover history replacement, pagination, stale paths, missing turns, subsequent turns, active-turn interruption, and preserved thread settings.
GitOrigin-RevId: 435a8163ad4f310cc47219b436f6bdde21f2b83a
Brandon Zhang