Fix: add ZipArchive guard to export-files.php, add composer install step + composer.json sync to deploy recipe

app/public/admin/actions/export-files.php

@@ -17,6 +17,12 @@ require_once APP_ROOT . '/src/Controllers/ExportController.php';
 require_once APP_ROOT . '/src/AdminLogger.php';
 require_once APP_ROOT . '/src/ErrorHandler.php';
 
+if (!class_exists('ZipArchive')) {
+    http_response_code(500);
+    header('Content-Type: text/html; charset=UTF-8');
+    exit('Module PHP <code>zip</code> non installé sur le serveur. Contactez l\'administrateur système (<code>apt install php8.4-zip</code>).');
+}
+
 try {
     $controller = ExportController::create();