One async task per managed server owns all state transitions via a
tokio::select! loop over cmd_rx and wait_child. Includes RealSpawner
and a smoke test covering the Start → Running → exit → Stopped →
Shutdown happy path.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Append RealChild (real tokio::process::Child wrapper) and spawn_with_logs
to child.rs. Uses nix::unistd::setpgid via tokio's re-exported pre_exec
to create an own process group, and fires per-stream log pump tasks that
drain stdout/stderr into the provided LogSink. terminate/kill signal the
whole process group via kill(-pgid, SIG*).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Adds kdl_parse module with parse_server_config() that deserialises a
KDL document into ServerConfig, with full validation of name, types,
durations, and restart/stop blocks. Also derives Default on
RestartPolicy to satisfy clippy.