feat(comments): add character limit to comment markdown body

Add an optional `$limit` parameter to `CommentPresenter::markdownBody()`
that truncates the comment body before rendering Markdown. The comment
partial now passes a default limit of 250 characters, preventing long
comments from dominating the layout. Unit tests cover rendering with and
without a limit.

app/Models/Presenters/CommentPresenter.php

@@ -14,9 +14,15 @@ class CommentPresenter
         $this->comment = $comment;
     }
 
-    public function markdownBody()
+    public function markdownBody(?int $limit = null)
     {
-        return Str::of($this->comment->body)->markdown([
+        $body = $this->comment->body;
+
+        if ($limit !== null) {
+            $body = Str::limit($body, $limit);
+        }
+
+        return Str::of($body)->markdown([
             'html_input' => 'strip',
         ]);
     }

resources/views/partials/comment.blade.php

@@ -14,7 +14,7 @@
                 @endif
             </div>
             <div class="mt-1 flex-grow w-full">
-                <div class="text-gray-700 dark:text-gray-200">{!! $comment->presenter()->markdownBody() !!}</div>
+                <div class="text-gray-700 dark:text-gray-200">{!! $comment->presenter()->markdownBody($limit ?? 250) !!}</div>
             </div>
             <div class="mt-2 space-x-2">
                 <span class="text-gray-500 dark:text-gray-300 font-medium">

tests/Unit/CommentPresenterTest.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace Tests\Unit;
+
+use App\Models\Comment;
+use Tests\TestCase;
+
+class CommentPresenterTest extends TestCase
+{
+    public function test_markdown_body_renders_full_comment_without_limit(): void
+    {
+        $comment = new Comment(['body' => 'Hello **world**']);
+
+        $result = (string) $comment->presenter()->markdownBody();
+
+        $this->assertStringContainsString('Hello', $result);
+        $this->assertStringContainsString('world', $result);
+    }
+
+    public function test_markdown_body_is_truncated_when_limit_is_provided(): void
+    {
+        $body = str_repeat('a very long comment. ', 50);
+        $comment = new Comment(['body' => $body]);
+
+        $result = (string) $comment->presenter()->markdownBody(40);
+
+        $this->assertLessThan(strlen($body), strlen($result));
+        $this->assertStringContainsString('...', $result);
+    }
+
+    public function test_markdown_body_is_not_truncated_when_body_is_shorter_than_limit(): void
+    {
+        $comment = new Comment(['body' => 'Short']);
+
+        $result = (string) $comment->presenter()->markdownBody(100);
+
+        $this->assertStringContainsString('Short', $result);
+        $this->assertStringNotContainsString('...', $result);
+    }
+}