Codex Version Upgrade

Use this skill to upgrade the built-in Codex version in this repository safely and predictably.

This repo does not rely on an ambient global codex installation. It pins a specific Codex release and threads that version through:

• host-mode managed binary download
• repo-managed pinned binary cache
• generated Codex App Server protocol artifacts
• agent-runner protocol mirror
• container image build

Because of that, a Codex upgrade is never just "change one version string and build". Treat it as a small compatibility migration with required verification.

What success looks like

A successful upgrade means all of the following are true: