fix(pay): preserve order note JSON, shared coupon burn, plate free VIP cashier

- Order_Repository: status note merges into JSON as status_note instead of wiping coupon/topic_pay meta
- Extract aksrt_burn_order_coupon / aksrt_coupon_usage_exists for content + topic
- Money plate follow (incl. VIP free) always opens multi-gateway cashier for 0-order ledger

inc/classes/class-aksrt-plate-follow-pay.php

@@ -616,6 +616,9 @@ class AKSRT_Plate_Follow_Pay {
     }
 
     private function decode_order_note_meta(array $order): array {
+        if (isset($order['meta_payload']) && is_array($order['meta_payload']) && $order['meta_payload'] !== []) {
+            return $order['meta_payload'];
+        }
         $note = (string) ($order['note'] ?? '');
         if ($note === '') {
             return [];