feat(vip): implement layered membership expiry flow

src/Content/VipService.php

@@ -30,6 +30,9 @@ class VipService {
     public function init(): void {
         add_action('rest_api_init', [$this, 'register_routes']);
         add_action('aksrt_order_paid', [$this, 'on_order_paid'], 20, 2);
+        if (class_exists(VipMembershipExpiry::class)) {
+            VipMembershipExpiry::init();
+        }
     }
 
 }