Exclude non-content files from build, remove old event page

Exclude README.md, LICENSE.md, and CLAUDE.md from Jekyll build
to prevent them from being indexed as duplicate pages by Google.
Remove outdated GSConnect 2024 event page.

Author: behas

_config.yml

@@ -61,6 +61,9 @@ exclude:
   - node_modules
   - update_boostrap.sh
   - cache
+  - README.md
+  - LICENSE.md
+  - CLAUDE.md
 
 titles_from_headings:
   enabled: false