//! The default `arora` binary: the headless device runner.
//!
//! It reads its configuration from the environment (Firebase options, Zenoh
//! endpoints, identity file), loads/saves an encrypted refresh token locally,
//! connects to Semio Studio over Zenoh, and runs the arora runtime. See
//! [`arora::headless`] for the configuration env vars and the full run.
//!
//! A device-specific build is a thin downstream binary that depends on `arora`
//! plus its own HAL/bridge crates and calls [`arora::launch`] /
//! [`arora::launch_with`] with those implementations — customization from the
//! outside, no feature flags inside `arora`.