Codex loads bundled plugin lifecycle hooks from `hooks/hooks.json` using a
strict schema that accepts only the top-level `hooks` field. The
plugin-packaged manifest carried a top-level `description`, so Codex rejected
the whole manifest with `unknown field description, expected hooks` and the
post-edit design detector never registered (issue #330).
Drop `description` from `buildClaudePluginHooksManifest()` and regenerate
`plugin/hooks/hooks.json`. The Claude Code plugin path is unaffected (it only
reads the `hooks` object). Add a regression assertion for the plugin artifact
and bump the skill version to 3.9.1.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013GTTHY6uHwESUyAgjUEm7x