Stale timer bodies were re-delivered to the orchestrator pane after
the parent had already processed the sub-agent's reply and called
close_process. The timer registry held no link to the child
lifecycle, so timers owned by or watching the closed child lingered
until something triggered a fire — e.g. a trailing classifier tick
for the now-removed child.
Add an OnChildClosed hook to ChildEventListener, emit it from
Session.Close (and the terminal-corpse path in reapChild), and have
the timer manager prune the registry: cancel timers owned by the
closed child; remove the closed child from each timer's watched
list (cancel the timer outright when watched empties).
Natural exit deliberately does not route through this hook — the
classifier already emits an idle transition on exit which delivers
any legitimate "fire when sub-agent finishes" semantics exactly
once; cancelling on exit would swallow that.
Harry Bayliss
34b41be1df