Fix: add jekyll-gist and jekyll-paginate to Gemfile

These were previously pulled in transitively via github-pages gem.
Now that github-pages is removed they must be listed explicitly.

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

Author: oguz-colak

Gemfile

@@ -5,6 +5,8 @@ gem 'jekyll', '~> 4.3'
 group :jekyll_plugins do
   gem 'jekyll-polyglot', '~> 1.7'
   gem 'jekyll-feed'
+  gem 'jekyll-gist'
+  gem 'jekyll-paginate'
   gem 'jekyll-sitemap'
   gem 'jekyll-redirect-from'
   gem 'jemoji'