feat: link docs site header to landing page

Set extra.homepage so the site title navigates to
https://towlion.github.io/ instead of the docs index.

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

Author: baijum

mkdocs.yml

@@ -23,6 +23,9 @@ theme:
     text: IBM Plex Sans
     code: JetBrains Mono
 
+extra:
+  homepage: https://towlion.github.io/
+
 extra_css:
   - stylesheets/custom.css