feat: initial release of relaticle/comments

Filament comments package with:
- Polymorphic commenting on any Eloquent model
- Threaded replies with configurable depth
- @mentions with autocomplete and user search
- Emoji reactions with toggle and who-reacted tooltips
- File attachments via Livewire uploads
- Reply and mention notifications via Filament notification system
- Thread subscriptions for notification control
- Real-time broadcasting (opt-in Echo) with polling fallback
- Dark mode support
- CommentsAction, CommentsTableAction, CommentsEntry for Filament integration
- 204 tests, 421 assertions

src/Policies/CommentPolicy.php

@@ -0,0 +1,36 @@
+<?php
+
+namespace Relaticle\Comments\Policies;
+
+use Illuminate\Contracts\Auth\Authenticatable;
+use Relaticle\Comments\Comment;
+
+class CommentPolicy
+{
+    public function viewAny(Authenticatable $user): bool
+    {
+        return true;
+    }
+
+    public function create(Authenticatable $user): bool
+    {
+        return true;
+    }
+
+    public function update(Authenticatable $user, Comment $comment): bool
+    {
+        return $user->getKey() === $comment->user_id
+            && $user->getMorphClass() === $comment->user_type;
+    }
+
+    public function delete(Authenticatable $user, Comment $comment): bool
+    {
+        return $user->getKey() === $comment->user_id
+            && $user->getMorphClass() === $comment->user_type;
+    }
+
+    public function reply(Authenticatable $user, Comment $comment): bool
+    {
+        return $comment->canReply();
+    }
+}