fix(docs): register cron-script-only guide in sidebar (#19893)

PR #19709 added website/docs/guides/cron-script-only.md but never added the entry to website/sidebars.ts, which is explicitly enumerated (not autogenerated). Two consequences:

1. The guide didn't show up in the left-nav "Guides & Tutorials" list — users could only reach it via cross-links from other pages.
2. Landing on the guide page directly made the sidebar disappear entirely (Docusaurus treats unregistered docs as orphaned and renders them without their parent sidebar).

Added 'guides/cron-script-only' next to 'guides/automate-with-cron' so it slots in alongside the other cron content. Verified with `npm run build`: no orphan warnings, no broken links, page builds with sidebar intact.

No content change, docs only.

Author: teknium1

website/sidebars.ts

@@ -168,6 +168,7 @@ const sidebars: SidebarsConfig = {
         'guides/use-voice-mode-with-hermes',
         'guides/build-a-hermes-plugin',
         'guides/automate-with-cron',
+        'guides/cron-script-only',
         'guides/automation-templates',
         'guides/cron-troubleshooting',
         'guides/work-with-skills',