Send delayed alert for new private channel messages

Private channel messages can trigger duplicate alerts and disrupt triage for on-call staff. Receive paced alerts and a logged timestamp so teams can triage before the next shift.

Overview

Noisy private-channel pings can drown out real incidents and create duplicate work for on-call staff. This flow buffers those messages, logs a timestamped record, and emits a single paced alert so support leads can triage within minutes and avoid repeated notifications.