v0.2.1

Changelog

• f17aea0 Update print statement from 'Hello' to 'Goodbye'
• c6021d5 ci(cd): add production/staging Docker Hub deploy → labmgm/mgm-cli
• a544f56 ci: fix vet (copylocks), alpine gcompat, package-install arch glob
• 3faabc5 feat: Megumi Code — broker-brokered AI coding agent (CLI phases 1–5)