* Add skills system with Claude Code compatibility
* consolidate skills into single module, merge loaders, add <available_skills> XML tags
* add Codex CLI skills compatibility, skip hidden/symlinks
- Parse --version and -v flags in args.ts
- Handle version flag early in main.ts (print and exit)
- Add flag to help text
- Add comprehensive test coverage for CLI arg parsing
Co-authored-by: cc-vps <crcatala+vps@gmail.com>