Keep queued messages visible at bottom of chat until processing starts

When sending a message while Claude is still working (queue), the queued message disappears from view. It would be helpful if the queued message stayed pinned at the bottom of the chat until Claude starts processing it, so the user has clear feedback that their message is waiting in the queue.

Current behavior: Queued message is not visually persistent after sending.

Expected behavior: The queued message remains visible/pinned at the bottom of the chat until Claude begins processing it.