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/CommentsPlugin.php

@@ -0,0 +1,37 @@
+<?php
+
+namespace Relaticle\Comments;
+
+use Filament\Contracts\Plugin;
+use Filament\Panel;
+
+class CommentsPlugin implements Plugin
+{
+    public function getId(): string
+    {
+        return CommentsServiceProvider::$name;
+    }
+
+    public function register(Panel $panel): void
+    {
+        //
+    }
+
+    public function boot(Panel $panel): void
+    {
+        //
+    }
+
+    public static function make(): static
+    {
+        return app(static::class);
+    }
+
+    public static function get(): static
+    {
+        /** @var static $plugin */
+        $plugin = filament(app(static::class)->getId());
+
+        return $plugin;
+    }
+}