Remove unsupported top-level description from hooks.json

Summary

plugins/codex/hooks/hooks.json currently contains a top-level description field before hooks. The Codex plugin hooks parser rejects that file with:

failed to parse plugin hooks config .../hooks/hooks.json: unknown field `description`, expected `hooks`

Proposed fix

Remove the unsupported top-level description field so the file has a single top-level hooks key. Keep the existing SessionStart, SessionEnd, and Stop hook entries unchanged.

I also prepared a local patch that adds a regression assertion to tests/commands.test.mjs:

const config = JSON.parse(source);
assert.deepEqual(Object.keys(config), ["hooks"]);

Validation

From a clean local clone at v1.0.6 plus the patch:

python3 -m json.tool plugins/codex/hooks/hooks.json
npm test

npm test passed: 91 tests, 91 pass, 0 fail.

Notes

I could not open a PR directly because this GitHub app installation does not have write access to openai/codex-plugin-cc, and the local gh token is currently invalid.

Inspect plugins/codex/hooks/hooks.json and the related assertion in tests/commands.test.mjs. Run python3 -m json.tool on the hooks file, then npm test. Done means the JSON has only the top-level hooks key, the existing SessionStart, SessionEnd, and Stop entries remain unchanged, and all tests pass.