## What changed
- Move parsing of pre-discovered executor skill bundles from `core-skills` to
the skills extension.
- Expose shared `SKILL.md` frontmatter parsing from `codex-skills` so direct
and pre-discovered loading use the same validation and repair behavior.
## Testing
- Add parity coverage for direct and pre-discovered executor skill catalogs,
including plugin namespaces, metadata, product policy, and warnings.
- Add a snapshot for the resulting pre-discovered executor catalog.
GitOrigin-RevId: c5f888226fa5600bd8b90f5682400da39a5db5ff
