feat: align comments redesign with new partials structure

- Re-applied redesign to new partial templates (_comment.html, _reply.html, etc.)
- Preserved HTMX and reactions functionality from v2 update
- Improved spacing and typography across all comment components
- Verified all E2E tests pass with new structure

templates/comments/_comment_list.html

@@ -1,4 +1,4 @@
-<div id="comments-list" class="space-y-8 mb-12"
+<div id="comments-list" class="space-y-12 mb-16"
   hx-get="{% url 'comment_poll' article_id=page.id %}" hx-trigger="every 30s" hx-swap="innerHTML">
   {% for comment in approved_comments %}
     {% include "comments/_comment.html" with comment=comment page=page %}