feat(oauth): add OAuth token support

readme.md

@@ -428,6 +428,27 @@ const payment = await BunqPayment.builder(bunq, account)
 // The same request ID will return the original payment without creating a duplicate
 ```
 
+### OAuth Token Support
+
+```typescript
+// Using OAuth access token instead of API key
+const bunq = new BunqAccount({
+  apiKey: 'your-oauth-access-token',  // OAuth token from bunq OAuth flow
+  deviceName: 'OAuth App',
+  environment: 'PRODUCTION',
+  isOAuthToken: true  // Important: Set this flag for OAuth tokens
+});
+
+await bunq.init();
+
+// OAuth tokens already have an associated session from the OAuth flow,
+// so the library will skip session creation and use the token directly
+const accounts = await bunq.getAccounts();
+
+// Note: OAuth tokens have their own expiry mechanism managed by bunq's OAuth server
+// The library will not attempt to refresh OAuth tokens
+```
+
 ### Error Handling
 
 ```typescript