review code pattern consistency

app/revenue/api/engine/manage_order.php

@@ -7,11 +7,13 @@ $action = $data['action'] ?? '';
 $data['items'] = json_decode($data['items'] ?? '[]', true) ?: [];
 
 if (!in_array($action, ['create', 'update'], true)) {
-    exit(json_encode(['success' => 0, 'message' => 'Unknown action']));
+    $answer['message'] = 'Unknown action';
+    exit(json_encode($answer));
 }
 
 if (empty($data['items'])) {
-    exit(json_encode(['success' => 0, 'message' => 'At least one item is required']));
+    $answer['message'] = 'At least one item is required';
+    exit(json_encode($answer));
 }
 
 try {
@@ -51,4 +53,3 @@ try {
 }
 
 exit(json_encode($answer));
-?>