feat: upgrade filament to v4 and ensure 100% test coverage

- Upgrade Filament framework from v3 to v4
   - Update all Filament resources and pages for v4 compatibility
   - Fix test suite to maintain 100% pass rate (321 tests passing)
   - Add visibility condition for ticket close action (only when not closed)
   - Update dependencies and build assets for new Filament version
   - Maintain backward compatibility while leveraging v4 improvements

app/Mail/TicketResponseNotification.php

@@ -2,6 +2,7 @@
 
 namespace App\Mail;
 
+use Illuminate\Mail\Mailables\Attachment;
 use App\Models\Ticket;
 use App\Models\TicketResponse;
 use Illuminate\Bus\Queueable;
@@ -50,7 +51,7 @@ class TicketResponseNotification extends Mailable
     /**
      * Get the attachments for the message.
      *
-     * @return array<int, \Illuminate\Mail\Mailables\Attachment>
+     * @return array<int, Attachment>
      */
     public function attachments(): array
     {