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

tests/Pest.php

@@ -0,0 +1,6 @@
+<?php
+
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Relaticle\Comments\Tests\TestCase;
+
+uses(TestCase::class, RefreshDatabase::class)->in('Feature');