- Update bilingual plugin README to use official marketplace as default install path.
- Keep manual paste installation as fallback and sync docs mirrors.
- Keep version unchanged at 0.2.1.
- Add GitHub skills-directory auto-discovery for install_skill batch install from tree root URLs.
- Harden language detection with frontend-first fallback (__event_call__ + timeout), then headers/profile.
- Bump plugin/docs versions to 0.2.1 and sync bilingual README/docs/index entries.