Extract persisted history types into a dedicated crate (#37871)

## 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

codex-rs/rollout/src/policy.rs

@@ -1,5 +1,5 @@
+use crate::RolloutItem;
 use crate::protocol::EventMsg;
-use crate::protocol::RolloutItem;
 use codex_extension_items::ExtensionItem;
 use codex_protocol::items::TurnItem;
 use codex_protocol::models::ResponseItem;