US-1: Receiving a reply while reading history

Given the user is scrolled up in a chat reading older messages When a new message arrives Then the chat does NOT auto-jump to the bottom And a subtle “New messages” indicator appears (e.g., a small pill/badge near the compose bar) And the user can press a button to jump to the newest message

US-2: Receiving a reply while at the bottom

Given the user is at the bottom of the chat (most recent message visible) When a new message arrives Then the new message appears smoothly at the bottom And the view auto-scrolls to show it And the selection index updates to the new message

US-3: Sending a message and seeing it appear

Given the user sends a message via the compose bar When the send succeeds Then the sent message appears in the chat immediately (optimistic UI) And the chat auto-scrolls to show it