[FEATURE] codex integration

## Feature Description

I realize this will likely be marked as out of scope, but I figured I would try. Worst case, it'll stick around in closed issues as a warning to others.

I quite enjoyed this plugin up until I switched to codex recently. It would be nice to have it continue working, especially after I spent time setting things up.

Any effort here would be appreciated and I am happy to help test. Thank you!

No files, tests, or entry points are named. Begin by reviewing the existing Claude Code integration and determining how Codex should be supported; clarify the expected behavior and acceptance criteria with maintainers before implementation. Done means the plugin continues working for Codex users and the integration is covered by appropriate verification.

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