BaseChannelListener.listen() only called pubsub.unsubscribe() in its
finally block: the pubsub connection and the listener's own Redis client
were never released, leaking a connection for every install/uninstall
(_watcher) and every recreation of the app-status listener. The Celery
task notifiers were likewise never closed, and used the deprecated
Redis.close() instead of aclose().
- add aclose() to BaseChannelNotifier and BaseChannelListener
- listen() now closes the pubsub and its Redis client in finally
- close the notifiers in the app_manage / app_status_update tasks and
switch to aclose()
- back off in the app-status watch loop so a Redis outage no longer
spins, and drop a leftover debug print
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>