//! RelayRL client runtime.
//!
//! This module is split into a small public API surface and a larger internal runtime:
//! - [`agent`]: public construction and control APIs for client applications
//! - `runtime::coordination`: coordinator, lifecycle, scaling, and state management
//! - `runtime::router`: message routing between actors and data sinks
//! - `runtime::data`: local file sinks plus experimental transport-backed sinks
//!
//! In `0.5.0-beta`, the supported path is the local/default runtime exposed through
//! [`agent`]. Transport-backed flows behind `zmq-transport` and `nats-transport` remain
//! experimental.
//!
//! The local/default runtime follows this flow:
//! `AgentBuilder` -> `RelayRLAgent` -> coordinator -> router/actors -> local file sink.
pub