Add unlisted frontmatter to home-pro compat stub and document exclusion

- Add `unlisted: true` and `description` frontmatter to docs/pro/home-pro.md
  to suppress Docusaurus "not in any sidebar" build warning
- Note pro/home-pro in sidebars.ts excluded-files comment for discoverability

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: justin808

docs/pro/home-pro.md

@@ -1,3 +1,8 @@
+---
+unlisted: true
+description: Compatibility stub — use the React on Rails Pro landing page instead.
+---
+
 # React on Rails Pro Home
 
 This route is kept for compatibility with older docs links.

docs/sidebars.ts

@@ -5,6 +5,7 @@ import type { SidebarsConfig } from '@docusaurus/plugin-content-docs';
 // - building-features/rails-webpacker-react-integration-options
 // - deployment/troubleshooting-when-using-webpacker
 // - misc/asset-pipeline
+// - pro/home-pro (URL-compatibility stub → pro/react-on-rails-pro)
 //
 // Contributing/Resources pages (linked from introduction.md instead of sidebar):
 // - misc/doctrine