Review round 3 (planner-reviewer-codex-01, NOT PASS R3 at 7e1d3f0):
start_timer stopped a running timer with a bare TERM and overwrote the only
pidfile. A beat the old timer had already admitted - seq taken, recorded on
disk, held at the wire - stayed alive but undiscoverable, so a later
terminal publish drained only the replacement and the old beat could still
put a retained `running` on the broker after `completed`.
- heartbeat.start_timer: stop_timer(drain=MAM_HEARTBEAT_DRAIN_S). The old
timer is drained or killed, and confirmed gone, before the pidfile names
the new one. A terminal publish racing the replacement either drains the
same old pid or meets a new timer whose beats the barrier refuses.
- test: an old timer held at the wire after admission is replaced, then
the job completes; the old timer is gone before the handover and nothing
it held follows the terminal (fails on 7e1d3f0).
- docs: MESSAGING 4.3 no longer says any state resets the idle clock;
MESSAGING 2.5 and VERSIONS state the replacement rule; test count 26.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HCGpJXhSZasJLU38ksDghe