The 20s ws-orphan grace (14b50f5edd) interrupts a RUNNING turn whenever
the client is absent past the grace window — killing healthy long turns
on deliberate client absence (desktop closed, PC asleep, mobile
backgrounded, Electron tab-switch throttling, desktop update/relaunch).
The reaper now interrupts a detached running turn ONLY when BOTH the
client is absent past the grace AND the turn's activity clock is stale
(seconds_since_activity >= dashboard.ws_orphan_activity_stale_s,
default 600s — matching agent.turn_liveness.timeout_s semantics from
PR #99758). A detached-but-actively-producing turn keeps running to
completion (the sentinel transport already buffers detached emits);
a detached AND activity-stale turn is interrupted/reaped as today.
Non-running orphaned sessions keep current behavior. Reuses the
existing AIAgent.get_activity_summary() clock — no parallel tracker
(rejected in PR #4864).
Fixes#98028Fixes#100325