The bounded-grace join only applies where the overlap hazard lives: a
total-ceiling expiry over a still-streaming worker (#97488). The
idle-stall path keeps its prompt detachment so the stall-fallback retry
preserves the #76354 S3 latency contract (silence never approaches 2x
the idle budget); its late unwind stays safe behind the fence poison
and attempt-generation supersession.
Sabotage-verified regression tests: bounded-grace worker teardown on
ceiling (cooperative join + uninterruptible orphan with retained
lease), durable strategy/kind-stamped backoff that survives a simulated
gateway restart against a real temp SessionDB, success clearing the
backoff, superseded-attempt late results discarded, and the
transient-block signal (type-pinned against MagicMock agents).
Teknium