Add ephemeral threads capabilities. Only exposed through the `app-server` v2 The idea is to disable the rollout recorder for those threads.
## Summary Support updating Personality mid-Thread via UserTurn/OverwriteTurn. This is explicitly unused by the clients so far, to simplify PRs - app-server and tui implementations will be follow-ups. ## Testing - [x] added integration tests
Experimental flag that signals the end of the turn.
Initial type tweaking PR to make the diff of https://github.com/openai/codex/pull/9116 smaller This should not change any behavior, just adds some fields to types
Some extra tests for https://github.com/openai/codex/pull/8950