Function start_all 

pub async fn start_all(
    streams: &[StreamListenerConfig],
    timeouts: &TimeoutConfig,
    shutdown_rx: Receiver<bool>,
) -> Result<(), String>

Binds every configured stream listener and spawns its accept/receive loop.

Binding is fail-fast: the first bind error (or invalid config) is returned so startup can abort with a clear message. On success every listener is bound and running in its own detached task, and this returns immediately. Each loop stops accepting when shutdown_rx flips to true (in-flight relays/sessions are then dropped at process exit).