When a chat cannot be matched to an account owner, customers need an alternative to round-robin routing. Round-robin assigns chats sequentially to individual reps, but if that rep misses the notification, the conversation is lost or delayed with no reliable fallback.

Requested behavior: Add a "broadcast" routing mode where, instead of assigning to a single rep, the chat is surfaced to all available reps simultaneously (via Slack channel notification or inbox). The first rep to respond claims ownership.