docs: add infinity logo icon to site header for brand identity on GitHub Pages

The docs site was using the default Material for MkDocs icon in the
header and browser tab. The infinity icon represents the "while True"
loop concept at Ralphify's core.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: 2 people

mkdocs.yml

@@ -41,6 +41,7 @@ theme:
     - search.highlight
     - toc.follow
   icon:
+    logo: material/infinity
     repo: fontawesome/brands/github
 
 markdown_extensions: