                    // Complex return type: serialize to JSON and return as *u8 (NUL-terminated C string).
                    // The caller owns the returned pointer; they must free it via the C API.
                    // For now, return null to indicate the method is not yet implemented.
                    // TODO: implement JSON serialization for this complex return type.
                    _ = {{ ok_binding }};
                    if (out_result) |ptr| ptr.* = null;
                    return 0;
