refactor: replace custom textarea with Filament RichEditor and built-in mentions

Replace the custom Alpine.js textarea + mention system with Filament v5's
built-in RichEditor component and MentionProvider. This fixes Alpine scope
errors (showMentions/mentionResults not defined) that occurred during
Livewire DOM morphing inside Filament slide-over modals.

- Add InteractsWithForms + HasForms to Comments and CommentItem components
- Define commentForm(), editForm(), replyForm() with RichEditor + mentions
- Add CommentsConfig::makeMentionProvider() shared helper
- Update MentionParser to extract mention IDs from RichEditor HTML format
- Update Comment::renderBodyWithMentions() to use RichContentRenderer
- Remove all custom Alpine.js mention code from blade templates
- Backward compatible with existing plain text comments

src/CommentsConfig.php

@@ -4,6 +4,7 @@ namespace Relaticle\Comments;
 
 use App\Models\User;
 use Closure;
+use Filament\Forms\Components\RichEditor\MentionProvider;
 use Relaticle\Comments\Mentions\DefaultMentionResolver;
 use Relaticle\Comments\Models\Comment;
 use Relaticle\Comments\Policies\CommentPolicy;
@@ -173,4 +174,19 @@ class CommentsConfig
     {
         static::$resolveAuthenticatedUser = $callback;
     }
+
+    public static function makeMentionProvider(): MentionProvider
+    {
+        return MentionProvider::make('@')
+            ->getSearchResultsUsing(fn (string $search): array => static::getCommenterModel()::query()
+                ->where('name', 'like', "%{$search}%")
+                ->orderBy('name')
+                ->limit(static::getMentionMaxResults())
+                ->pluck('name', 'id')
+                ->all())
+            ->getLabelsUsing(fn (array $ids): array => static::getCommenterModel()::query()
+                ->whereIn('id', $ids)
+                ->pluck('name', 'id')
+                ->all());
+    }
 }