Companion runs record neither the resolved model nor which `codex` binary served them

Desktop runs leave a rollout file with cli_version and the model per turn. App-server companion rounds leave no session artifact, and neither the run output nor the job record states the resolved model or which codex binary served the run — the binary is PATH-decided and therefore silently swappable.

Why it matters: "which model reviewed which change" has to be unambiguous after the fact. We maintain a per-round record by hand purely because of this gap, which means the record is only as good as the discipline keeping it.

Ask: echo the resolved model id and the binary version in the run header (and, if practical, in the job record).

Adjacent data point, offered while filing: gpt-5.6-sol completes the structured-output adversarial path on CLI 0.144.1, so the gpt-5.4 pin in 1.0.3 appears obsolete on current state.

Related: #654 asks for --model to be documented on the review commands; this issue is about recording what was actually resolved.

Start by tracing app-server companion rounds from their run output to the job record, and compare them with the desktop rollout artifact that already records cli_version and the model per turn. Identify where the run header is assembled and where model and binary version are resolved. Done means the resolved model id and codex binary version are unambiguous in the run header, with the job record updated if practical.