rlmesh_ext_last_error_take_payload_owned

Tagged ownership transfer: the library never reads tag or payload bytes. The tag identifies a payload representation/owner domain. The legacy setter records a NULL tag. Use the returned deleter for foreign representations. On success, all outputs are initialized (NULL when empty); outputs must be distinct writable slots. All three are required. A failing call does not consume the payload. A successful take transfers the deleter obligation.

RLMeshStatus rlmesh_ext_last_error_take_payload_owned(
    void** out_payload,
    void (**out_free_payload)(void* payload),
    const void** out_tag
)