Follow-up on top of the salvaged #94095 commit:
- maybe_auto_prune_and_vacuum() now returns 'closed' (stale open state-owned
sessions marked ended) alongside 'pruned', so entrypoints can report the
reconciliation without parsing logs.
- Docstring explains the two-window lifecycle (close now, delete after a
further retention window).
- Regression test: cron/kanban/subagent rows with ended_at NULL are closed on
pass 1 and deleted on pass 2; a telegram row is never touched.
- website/docs sessions.md documents the automatic stale-open sweep.
Close session rows left ended_at IS NULL when the in-process websocket
orphan timer dies with the process (#65194). Dual-clock staleness
(started_at AND newest message), desktop included, live in-memory
sessions excluded, scheduled once from both entry.main and the WS
sidecar so desktop/dashboard boots also run the sweep.
Teknium