fix(new-setup): run probe before pnpm is installed

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>

setup/index.ts

@@ -19,7 +19,6 @@ const STEPS: Record<
   onecli: () => import('./onecli.js'),
   auth: () => import('./auth.js'),
   'cli-agent': () => import('./cli-agent.js'),
-  probe: () => import('./probe.js'),
 };
 
 async function main(): Promise<void> {