v2.0.0

v2.0.0: pin lockbox v2.1.2, restructure skill, update commands

BREAKING: file operation commands renamed to match lockbox v2.1.2
- ls -> list-files, rm -> remove-file, mkdir -> create-dir
- rmdir -> remove-dir, rrmdir -> remove-dir-recursive
- new: move-file, copy-file, file-info, file-exists, file-hash,
  disk-usage, search-files, append-file

- pin FROM psyb0t/lockbox:v2.1.2
- migrate skill from .openclaw/skills/ to .skills/ (qwenspeak style)
- add scripts/mediaproc.sh SSH wrapper with auto host key accept
- add references/setup.md for install/config docs
- update README file ops table with all lockbox commands
- fix test using old ls command