T5 — send_after addresses a registered atom name; the delayed message
lands in that process's mailbox (destination resolved at fire time,
dead/unregistered targets drop silently).
T6 — gen_server loop now handles the {reply,R,S,T} / {noreply,S,T}
timeout-bearing callback returns by scheduling {timeout} to itself via
send_after; handle_info({timeout}, S) fires when no other message
arrives first. Sanity-checks the library hookup.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
giles
779e53b2a8