Port probe to zero-dep plain ESM (setup/probe.mjs) so /new-setup can
inject dynamic context on a fresh machine where pnpm/node_modules
don't yet exist. Skill falls back to a STATUS: unavailable block if
Node itself isn't on PATH, and the flow treats that as "run every
step from 1" (each step is idempotent).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
