arlo:setup — alias of /arlo:start
setup and start are the same lifecycle action: first-time setup of arlo for this
project, run while the frontier is up. Follow /arlo:start — its bundled SKILL.md is
the procedure (resolve the model tier, harvest this project's ground truth into
.arlo/cards.json, write the lights-out fallback, and put arlo on the PATH).
After setup, keep arlo current with /arlo:update, and uninstall with /arlo:remove.