refactor(app): tighten feature boundaries

src/app/subscription/components/subscription-checkout-button.tsx

@@ -6,7 +6,7 @@
  */
 import { useEffect, useRef, useState } from "react";
 
-import { PendingPaymentOrderStorage } from "@/data/storage";
+import { savePendingEzpayOrder } from "@/lib/payment/pending_payment_order";
 import {
   usePaymentDispatch,
   usePaymentState,
@@ -280,12 +280,10 @@ async function launchEzpayRedirect({
     return;
   }
 
-  const saveResult = await PendingPaymentOrderStorage.setPendingOrder({
+  const saveResult = await savePendingEzpayOrder({
     orderId,
-    payChannel: "ezpay",
     subscriptionType,
     ...(returnTo ? { returnTo } : {}),
-    createdAt: Date.now(),
   });
   if (Result.isErr(saveResult)) {
     const errorMessage =