refactor(new-setup): rewrite probe in pure bash, drop unavailable fallback

The probe now returns a real snapshot from second zero, so every step
consults real probe fields instead of falling back to "run every step
blindly" when Node isn't installed. Also drops the redundant
CLI_AGENT_WIRED field (it gated the last step on its own end-state) and
scopes timezone out of the probe (timezone is not part of /new-setup).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

setup/onecli.ts

@@ -106,7 +106,7 @@ function installOnecli(): { stdout: string; ok: boolean } {
 }
 
 async function pollHealth(url: string, timeoutMs: number): Promise<boolean> {
-  // `/api/health` matches the path probe.mjs uses — keep them aligned.
+  // `/api/health` matches the path probe.sh uses — keep them aligned.
   const deadline = Date.now() + timeoutMs;
   while (Date.now() < deadline) {
     try {