RYMCU legacy site

The former RYMCU GitHub Pages site has been retired. Its public URL now sends visitors and search engines to the canonical site at https://rymcu.com/.

Publishing

• index.html redirects the root URL.
• nebula-pi-f103/index.html redirects the former product page to its maintained GitHub repository.
• 404.html returns a clean retirement notice for unknown legacy paths.
• robots.txt keeps the redirect pages crawlable so their noindex and canonical signals can be processed.

GitHub Pages publishes the master branch root directly. No application build, package installation, external license, or Actions workflow is required.

The previous Nuxt source remains available in Git history for reference. It is not present in the current tree and is no longer built or deployed.