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

assets/js/forum-governance.js

@@ -693,8 +693,9 @@
         payHint = payHint || {};
         var modo = String(payHint.modo || 'money');
 
-        // Cash: multi-gateway cashier (no Credits×100 bypass).
-        if (modo === 'money' && !payHint.is_free) {
+        // Cash (paid or VIP free): multi-gateway cashier — free VIP still creates 0-order for ledger.
+        // No Credits×100 bypass.
+        if (modo === 'money') {
             button.disabled = false;
             if (typeof window.aksrtOpenCashier === 'function') {
                 window.aksrtOpenCashier(plateId, button, '', '', 'plate_follow');
@@ -706,7 +707,7 @@
             return;
         }
 
-        // Points / VIP free: keep AJAX purchase path.
+        // Points / points VIP free: keep AJAX purchase path.
         var confirmMsg = '确认付费关注该版块？';
         if (payHint.is_free) {
             confirmMsg = '确认使用 VIP 免费关注该版块？';