## What changed
Introduce `ItemIdGenerator` and pass the runtime-owned generator through sessions, model clients, history, hooks, tool outputs, and memory requests. Keep UUIDv7 generation as the default and replace direct calls to `ResponseItemId::new` with the shared callable.
Preserve existing item IDs and backfill missing or empty IDs through the same generator, including forked history before reconstruction and persistence.
## Testing
Extend coverage for UUIDv7 IDs on user messages, agent messages, and additional tools, and assert that forked model context matches the backfilled items persisted to history.
GitOrigin-RevId: 0dd9ccf0f46f0f1005a6acfc740133b03ce82259
## Why
Compaction replaces the model history window, but host-verified user answers may
still be needed for the rest of the owning thread.
## What changed
- Add bounded, model-invisible retained context for verified
`request_user_input` answers.
- Persist retained context in rollout events and compaction checkpoints, and
restore it when a thread resumes.
- Remove answers when their source turns are rolled back, and prevent
parent-local answers from being inherited by child forks.
## Testing
Add lifecycle coverage for deduplication and size limits, compaction and resume,
rollback, rollout migration, and child forks.
GitOrigin-RevId: c32900d3e8120a9899b71f0576683acd67a4b898
## What changed
- Add `codex-history` for model-history and persisted-rollout domain types, including `RolloutItem`, `RolloutLine`, `CompactedItem`, and initial/resumed history state.
- Re-export the persisted types from `codex-rollout` and update consumers to use the new crate boundary instead of `codex-protocol`.
- Preserve existing rollout serialization, including legacy numeric compacted-window IDs.
## Testing
- Add `codex-history` tests for rollout JSON round trips, compacted-history compatibility, persisted history modes, and multi-agent version selection.
GitOrigin-RevId: 944daa9297ddd231d3aebbdcb05fff4adf8b4e1b
Ruslan Nigmatullin