rlmesh_env_server_address
New binds. start runs callbacks on library threads; serve keeps lane 0 on the caller. shutdown is allowed from a callback. Free shuts down and drains all C callbacks, including any still running past the facade's timeout.
RLMeshStatus rlmesh_env_server_address(
const RLMeshEnvServer* env_server,
RLMeshBytes* out
)