5.64.2

(fix): OpenAPI import: an endpoint that declares both a body-bearing 2xx response and a 204 No Content response now correctly produces an optional success body, even when the 204 erroneously declares a response body. Per RFC 9110 a 204 cannot carry a body, so the declared 204 body is ignored (with a warning) and the success response type is wrapped optional. Previously the 204 was dropped and the return type stayed non-optional, so a real 204 (empty body) failed to decode in generated SDKs. Applies to both the legacy and v3 OpenAPI importers.