Add independent PayPal hosted binding mode

tests/plus-checkout-address-input.test.js

@@ -38,7 +38,7 @@ test('plus checkout content script can be injected repeatedly on the same page',
   assert.equal(context.__MULTIPAGE_PLUS_CHECKOUT_READY__, true);
 });
 
-function createPlusCheckoutMessageHarness({ checkoutSessionId = 'cs_test_123' } = {}) {
+function createPlusCheckoutMessageHarness({ checkoutSessionId = 'cs_test_123', checkoutResponse = null } = {}) {
   const attrs = new Map();
   let listener = null;
   const fetchCalls = [];
@@ -84,7 +84,7 @@ function createPlusCheckoutMessageHarness({ checkoutSessionId = 'cs_test_123' }
         return {
           ok: true,
           status: 200,
-          json: async () => ({ checkout_session_id: checkoutSessionId }),
+          json: async () => (checkoutResponse || { checkout_session_id: checkoutSessionId }),
         };
       }
       throw new Error(`unexpected fetch url: ${url}`);
@@ -153,6 +153,40 @@ test('CREATE_PLUS_CHECKOUT uses ID/IDR and openai_llc merchant path for GoPay',
   });
 });
 
+test('CREATE_PLUS_CHECKOUT uses hosted US/USD checkout for PayPal no-card binding', async () => {
+  const hostedUrl = 'https://pay.openai.com/c/pay/cs_hosted_123';
+  const harness = createPlusCheckoutMessageHarness({
+    checkoutSessionId: 'cs_hosted',
+    checkoutResponse: {
+      checkout_session_id: 'cs_hosted',
+      next_action: {
+        redirect_to_url: {
+          url: hostedUrl,
+        },
+      },
+    },
+  });
+
+  const result = await harness.send({
+    type: 'CREATE_PLUS_CHECKOUT',
+    source: 'test',
+    payload: { paymentMethod: 'paypal-hosted' },
+  });
+
+  assert.equal(result.ok, true);
+  assert.equal(result.checkoutUrl, 'https://chatgpt.com/checkout/openai_llc/cs_hosted');
+  assert.equal(result.hostedCheckoutUrl, hostedUrl);
+  assert.equal(result.preferredCheckoutUrl, hostedUrl);
+  assert.equal(result.country, 'US');
+  assert.equal(result.currency, 'USD');
+
+  const checkoutCall = harness.fetchCalls.find((call) => call.url === 'https://chatgpt.com/backend-api/payments/checkout');
+  assert.ok(checkoutCall);
+  const payload = JSON.parse(checkoutCall.options.body);
+  assert.equal(payload.checkout_ui_mode, 'hosted');
+  assert.deepEqual(payload.billing_details, { country: 'US', currency: 'USD' });
+});
+
 function extractFunction(name) {
   const plainStart = source.indexOf(`function ${name}(`);
   const asyncStart = source.indexOf(`async function ${name}(`);