Add filename param support with Content-Disposition header

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/Controllers/GenerateController.php

@@ -60,7 +60,9 @@ class GenerateController
             }
 
             // Retourner le PDF
+            $filename = !empty($data['filename']) ? basename($data['filename']) : 'document.pdf';
             header('Content-Type: application/pdf');
+            header('Content-Disposition: attachment; filename="' . $filename . '"');
             header('Content-Length: ' . strlen($pdf));
             echo $pdf;