Two follow-up improvements to the previous commit's notifier dedup work.
1. Add a regression test for the send-exception rewind path. The
contributor's PR included a test for the adapter-disconnect path
(test_kanban_notifier_rewinds_claim_if_adapter_disconnects, where
adapter is None at delivery time), but not for the "adapter is
connected, send() raises" path that fires inside the inner try/except
at gateway/run.py:4314. The new test
(test_kanban_notifier_rewinds_claim_on_send_exception) uses a
FailingAdapter that always raises and confirms (a) send was actually
attempted, (b) the claim was rewound, (c) the next call to
unseen_events_for_sub still returns the event for retry.
2. Drop the per-delivery success log from INFO to DEBUG. A busy board
on a multi-platform gateway can produce hundreds of these per day;
that's gateway.log noise that obscures real warnings. Failure paths
stay at WARNING (where you'd want to look when something's wrong)
so we don't lose visibility into transient send issues.
