- extract _commit_registry/_note_refresh_failure shared by the background
worker and foreground stage-4 (identical 4-step success + failure paths
were duplicated); worker now commits under _models_dev_fetch_lock so a
failing background refresh can never re-arm the backoff immediately
after a successful force_refresh committed (unsynchronized-write race)
- add should_clear_context_pin_async to hermes_cli/route_identity.py
(matching the get_model_context_length_async precedent) and use it at
the 4 async gateway sites instead of inline asyncio.to_thread wraps;
the sync _format_session_info site keeps the sync call (already
off-loop via its callers' to_thread)
- test the background-refresh success path (the PR's primary new
behavior): disk saved, mem cache swapped, backoff cleared, in_flight
reset — mutation-checked
- replace the race-prone spin-wait on _models_dev_refresh_in_flight with
a named-thread join in the backoff test