Buzz now knows when to respond in shared threads

Buzz can now distinguish between messages meant for people and messages that call for Buzz. In shared threads, it stays quiet when one person is speaking to another, while responding to open-room questions and clear follow-ups addressed to Buzz.

Explicit @Buzz mentions continue to trigger a response. This keeps shared conversations focused while making it easier to get help when you need it.

**Who it helps: **Teams collaborating in shared threads get fewer interruptions and more relevant Buzz responses.