Provides a single command to run a livecd-rootfs build, replacing the
manual setup of auto/ symlinks and env vars that lpbuildd's
build_livefs.py encapsulates. Works from a git checkout, an installed
deb, or via the /usr/bin/build-livefs symlink.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>