feat: Handle 202 Accepted from /charge endpoint

The auth service now returns HTTP 202 for async payments that are accepted
but still processing. This change treats 202 the same as 200 (success).

- 200 = synchronous payment completed
- 202 = async payment accepted (balance checked, executing in background)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: badjer

packages/atxp-server/src/paymentServer.test.ts

@@ -102,6 +102,29 @@ describe('ATXPPaymentServer', () => {
     expect(parsedBody.options).toBeDefined();
   });
 
+  it('should handle charge endpoint returning 202 status (async payment accepted)', async () => {
+    const mock = fetchMock.createInstance();
+    mock.post('https://auth.atxp.ai/charge', {
+      status: 202,
+      body: {
+        success: true,
+        pending: true,
+        paymentRequestId: 'async-payment-123'
+      }
+    });
+
+    const oAuthDb = await createOAuthDbWithCredentials('https://auth.atxp.ai', 'test-client-id', 'test-client-secret');
+    const server = new ATXPPaymentServer('https://auth.atxp.ai', TH.logger(), mock.fetchHandler, oAuthDb);
+
+    const result = await server.charge(TH.charge({
+      sourceAccountId: 'solana:test-source',
+      destinationAccountId: 'solana:test-destination'
+    }));
+
+    // Verify the result indicates payment accepted (returns true)
+    expect(result).toBe(true);
+  });
+
   it('should handle charge endpoint returning 402 status (payment required)', async () => {
     const mock = fetchMock.createInstance();
     mock.post('https://auth.atxp.ai/charge', {

packages/atxp-server/src/paymentServer.ts

@@ -42,7 +42,8 @@ export class ATXPPaymentServer implements PaymentServer {
 
   charge = async(chargeRequest: Charge): Promise<boolean> => {
     const chargeResponse = await this.makeRequest('POST', '/charge', chargeRequest);
-    if (chargeResponse.status === 200) {
+    // 200 = synchronous success, 202 = accepted (async payment in progress)
+    if (chargeResponse.status === 200 || chargeResponse.status === 202) {
       return true;
     } else if (chargeResponse.status === 402) {
       return false;