d68c9db9f9
Re-review at 7286d320. -012 (Medium): DisconnectAsync now snapshots+nulls the data/alarm
subscriptions under _subscriptionLock before async teardown (was racing RunFailoverAsync).
-013: SubscribeAlarmsAsync guarded by a semaphore (idempotent under concurrency). -014/-015:
forward CancellationToken through Delete/BrowseNext adapters. + TDD.