docs: rename CLI-CREATOR → CLI-EXPLORER, add CLI-ONESHOT refs to READMEs

- Rename CLI-CREATOR.md → CLI-EXPLORER.md (explorer better reflects its purpose)
- Update all references across SKILL.md, README.md, README.zh-CN.md, CLI-ONESHOT.md
- Add quick-mode (CLI-ONESHOT) and full-mode (CLI-EXPLORER) entries in both READMEs