🐛 Render comments in the simple article layout

Extract the comments block into a shared article-comments partial and
include it from both single and simple layouts. Fixes #2938.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

layouts/_default/simple.html

@@ -11,8 +11,9 @@
     <section class="max-w-full mt-6 prose dark:prose-invert">
       {{ .Content }}
     </section>
-    <footer class="pt-8">
+    <footer class="pt-8 print:hidden">
       {{ partial "sharing-links.html" . }}
+      {{ partial "article-comments.html" . }}
     </footer>
   </article>
 {{ end }}