This PR changes get history op to get path. Then, forking will use a path. This will help us have one unified codepath for resuming/forking conversations. Will also help in having rollout history in order. It also fixes a bug where you won't see the UI when resuming after forking.
codex-protocol
This crate defines the "types" for the protocol used by Codex CLI, which includes both "internal types" for communication between codex-core and codex-tui, as well as "external types" used with codex mcp.
This crate should have minimal dependencies.
Ideally, we should avoid "material business logic" in this crate, as we can always introduce Ext-style traits to add functionality to types in other crates.