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/_reply.html

@@ -1,10 +1,14 @@
-<article id="comment-{{ comment.id }}" class="mt-6 ml-8 bg-zinc-50 dark:bg-zinc-900 border border-zinc-200 dark:border-zinc-800 border-l-2 border-l-brand-cyan p-4">
-  <div class="flex items-center gap-3 mb-2">
-    <div class="w-7 h-7 bg-gradient-to-tr from-brand-pink to-brand-cyan shrink-0"></div>
-    <div>
-      <div class="font-display font-bold text-sm">{{ comment.author_name }}</div>
-      <div class="font-mono text-xs text-zinc-500">{{ comment.created_at|date:"M j, Y" }}</div>
+<article id="comment-{{ reply.id }}" class="bg-zinc-50/50 dark:bg-zinc-900/30 border border-zinc-100 dark:border-zinc-800 p-5 sm:p-6">
+  <div class="flex items-start gap-3 mb-3">
+    <div class="w-8 h-8 bg-gradient-to-tr from-brand-pink to-brand-cyan shrink-0 rounded-sm"></div>
+    <div class="flex-1 min-w-0">
+      <div class="flex flex-wrap items-baseline gap-x-2">
+        <span class="font-display font-bold text-sm text-zinc-900 dark:text-zinc-100">{{ reply.author_name }}</span>
+        <time datetime="{{ reply.created_at|date:'c' }}" class="font-mono text-[10px] text-zinc-400 uppercase tracking-wider">{{ reply.created_at|date:"M j, Y" }}</time>
+      </div>
+      <div class="mt-2 prose prose-sm dark:prose-invert max-w-none text-zinc-600 dark:text-zinc-400 leading-relaxed text-sm">
+        {{ reply.body|linebreaks }}
+      </div>
     </div>
   </div>
-  <p class="text-zinc-700 dark:text-zinc-300 text-sm leading-relaxed">{{ comment.body }}</p>
 </article>