revert(payment): remove unsupported Stripe and EzPay upgrade

src/lib/payment/__tests__/payment_launch.test.ts

@@ -2,7 +2,6 @@ import { describe, expect, it, vi } from "vitest";
 
 import {
   getPaymentUrl,
-  getStripeCustomerSessionClientSecret,
   getStripeClientSecret,
   isEzpayPayment,
   launchEzpayRedirect,
@@ -44,28 +43,6 @@ describe("payment launch helpers", () => {
     ).toBeNull();
   });
 
-  it("enables saved cards only with an explicit flag and a Customer Session secret", () => {
-    expect(
-      getStripeCustomerSessionClientSecret({
-        provider: "stripe",
-        customerSessionClientSecret: "cuss_123_secret_456",
-        savedPaymentMethodsEnabled: true,
-      }),
-    ).toBe("cuss_123_secret_456");
-    expect(
-      getStripeCustomerSessionClientSecret({
-        customerSessionClientSecret: "cuss_123_secret_456",
-        savedPaymentMethodsEnabled: false,
-      }),
-    ).toBeNull();
-    expect(
-      getStripeCustomerSessionClientSecret({
-        customerSessionClientSecret: "invalid-customer-session",
-        savedPaymentMethodsEnabled: true,
-      }),
-    ).toBeNull();
-  });
-
   it("resolves Ezpay URL and QR launch parameters without treating QR data as a URL", () => {
     expect(
       resolveEzpayLaunchTarget({