Module spawn 

Canonical child-session spawn core (anti-fork single implementation).

run_child_spawn is the one place that loads a child session, reserves its runner, wires the event forwarder + heartbeat + watchdog, builds the full [ExecuteRequest], runs the child loop, and publishes the terminal child completion. Both the background scheduler (run_spawn_job) and the ergonomic crate::sdk::runner::ChildRunner delegate here so behavior — event ordering, status strings, and field set — stays identical across entry points.

Functions

run_child_spawn

Launch a single child spawn job.