ce71fac7d6
- Prime app_mention retry allowance before dedupe so near-simultaneous message/app_mention races do not drop valid mentions. - Prevent duplicate dispatch when app_mention wins the race and message prepare later succeeds. - Prune dispatched mention keys and add regression coverage for both dropped and successful in-flight message outcomes. Co-authored-by: Tak Hoffman <781889+Takhoffman@users.noreply.github.com>