/start Endpoint Response Code Documentation

We've added comprehensive response code documentation for the /start endpoint, covering all expected HTTP status codes with detailed examples.

• 200 OK — Four integration pattern examples (Direct polling, Direct webhook, Capture with SMS, Capture with redirect).
• 400 Bad Request — 11 error examples across request errors and field validation errors, with guidance on resolution.
• 401 Unauthorized — Authentication failure scenarios.
• 404 Not Found — Route errors.
• 500 Internal Server Error — Server-side error handling.

checkResult & processResult Property Updates

We've updated the API reference to clarify the checkResult and processResult response properties.

• checkResult is now documented on the /barcode-only and /get-results endpoints with defined enum values (0–4).
• processResult is marked as deprecated — use checkResult instead. This is a documentation update only, not a breaking change.
• There is no change to the get-transaction-data endpoint. It retains the snake_case check_result property.