Retrieves the result of a previously created transactions request.

The response status is one of:

• pending — the request is still being processed; poll again.
• completed — the result is available in result.
• failed — the request could not be completed; see failure_reason.

This endpoint is idempotent and re-readable: repeated reads of the same request_id return the same pre-computed page.
To retrieve a different page, create a new request via POST with the next_cursor value, which returns a new request_id.

This API must be called using a client_credentials bearer token.