Claim-polling SchedulingConfigurer: claims due notifications, resolves instance/connection/rule, checks active silences, dispatches via WebhookDispatcher, classifies outcomes into DELIVERED/FAILED/retry. Guards null rule/env after deletion. 5 Testcontainers ITs: 200/503/404 outcomes, active silence suppression, deleted connection fast-fail. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>