Stalled sessions could leave a session lane occupied by an orphaned active task after the embedded run handle was gone. Diagnostics repeatedly reported the stuck state, but the lane stayed held and queued turns could remain blocked indefinitely.
Release ownerless active lane tasks after the stale threshold, while guarding against fresh lane work and raised compaction safety windows so recovery does not double-run serialized session work or overlap transcript compaction. Stalled model-call recovery also no longer requires an in-process embedded run handle, so no-handle stalls can be reclaimed by the existing conservative recovery path.
Refs #99847.
Refs #94650.
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