fix: make bake subcommand visible in --help and bump to 2.7.0

- Add epilog to main parser showing bake and @name subcommands
- Handle -h/--help in _handle_bake() with proper command listing
- Bump version to 2.7.0 (also sync __init__.py version)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>