docs: route queue heartbeat evidence gap

Assistant: codex
Assistant-Model: gpt-5.6-sol
Assistant-Session: 01a06bfe-2a55-7ed3-bacd-879977b099bf

workplans/ACTIVITY-WP-0036-queue-identity-and-lease-integrity.md

@@ -9,7 +9,7 @@ owner: codex
 topic_slug: activity-core
 priority: high
 created: "2026-08-23"
-updated: "2026-08-23"
+updated: "2026-09-04"
 related:
   - ACT-ADR-005
   - ACTIVITY-WP-0026
@@ -149,3 +149,14 @@ No run was claimed during the observation window, so a natural active
 heartbeat and rejected late close remain before T04 can be marked done. The
 sole open row was an intentionally non-automated retention record and was not
 modified to manufacture evidence.
+
+Follow-up 2026-09-04: 24 natural runs have been claimed since rollout and all
+terminated in 5–34 seconds. The rein consumer schedules its first heartbeat at
+one third of the 900-second lease, capped at 300 seconds, so production API
+logs contain accepted claim/fail traffic but zero heartbeat requests. This is
+an observability gap in the consumer timing, not evidence that Activity Core's
+lease enforcement is absent. State Hub message
+`1250c36a-9fe8-45dc-bb5a-d5fa85e49fd0` asks rein-aharness to heartbeat once
+immediately after claim, retain periodic heartbeats, and return a natural
+claim/heartbeat/close trace. It also requests an isolated labeled late-close
+smoke; no real workload will be delayed or expired to manufacture evidence.