magpie-setup

Adopt and maintain the apache-magpie framework in a project repo via the snapshot-based installation mechanism. The only framework skill committed in an adopter's repo; every other skill is a symlink the install sub-action wires up. Sub-actions: /magpie-setup — first-time install (default; main-checkout only). adopt is an alias. /magpie-setup upgrade — refresh the gitignored snapshot per the committed lock…