Time-bucket dedupe is not a rolling suppression window

Observation (2026-09-04 UTC), source provenance: read-only review of e3-solutions/theft PR #795 at head e23429c6 against origin/staging. A key built as floor(now/window) only deduplicates inside fixed wall-clock buckets: requests seconds apart on opposite sides of a boundary receive different keys. More generally, do not treat a durable logical-event claim as proof that a later external notification was delivered; if a UI acknowledges operator handoff, delivery needs an awaited/retryable or reconcilable durable boundary. Also claim idempotency before reopening issue state, otherwise a duplicate claim can commit a reopened issue while suppressing routing and notification. This is a reusable review check for support/notification workflows.