Chat threads keep conversations and ongoing work beside Chat

Organization owners and admins can turn on Chat threads in Settings > Features. With it on, the sidebar holds only Chat, and a Threads panel beside the permanent conversation lists your other conversations and the work running in the background.

Create a New thread, search conversations, and open work from its card, where you can answer pending input or stop it. Resolve thread puts a conversation away without losing history, and Reopen thread continues it. The panel becomes a drawer on mobile. Turning the feature off restores the previous Chat and keeps conversations and their URLs.

See Chat and Threads. PR #4146.