MuJoCo Menagerie Archives Use Git Tree IDs

Kevin Zakka stated that archives are named by each robot's git tree id. Specifying mujoco-menagerie==2026.9.0 in a lockfile therefore pins every model to that exact tag. Upgrades re-download only robots that changed. He added that the wheel itself is 30 KB and holds solely the Menagerie catalog. The catalog lists each robot, its license, and the location of its archive. Each robot ships as a separate archive on a GitHub release, fetched on first load, verified, and then cached.