codex-rs/docs/protocol_v1.md appears stale

What happened?

While reviewing the repo docs before considering a contribution, I noticed that codex-rs/docs/protocol_v1.md appears to be stale relative to the current protocol/core code.

A few examples:

• The opening sentence links to ../core/src/agent.rs, but codex-rs/core/src/agent.rs no longer exists. The Codex struct currently lives in codex-rs/core/src/session/mod.rs, while agent-related code is under codex-rs/core/src/agent/.
• The session section refers to Op::ConfigureSession, but I could not find a ConfigureSession variant in codex-rs/protocol/src/protocol.rs.
• The task/user input sections refer to Op::UserTurn as the current input operation and Op::UserInput as legacy, but the current Op enum defines UserInput.
• EventMsg::TurnComplete is listed twice in the example EventMsg bullet list.
• There are a few small prose/formatting issues, such as “These are entities exit on the codex backend”, “The Task executes to until”, “Has an string ID”, and the inline transport list under ## Transport.

Expected behavior

The protocol overview should either match the current codex-rs/protocol/src/protocol.rs and core session structure, or clearly identify which parts are historical/out-of-date. Internal links should resolve to existing files.

Additional context

I searched open issues and PRs for terms including protocol_v1, ConfigureSession, UserTurn, and core/src/agent.rs, and did not find an existing open issue that appears to cover this specific doc drift.