chore(gitignore): exclude *.original.md compress backups
/caveman:compress writes a human-readable backup as <file>.original.md
before overwriting. Backups are recoverable via git history (the
pre-compression state lives in the previous commit), so committing
them duplicates content and bloats the repo.
Globbing on *.original.md catches all compressed registries plus
CLAUDE.original.md.
Co-Authored-By: Claude <noreply@anthropic.com>
