Scroll to the latest message in long running threads

## Motivation
When opening or returning to an existing chat thread, the view fails to automatically scroll to the bottom. Instead of anchoring at the end with the latest content, the layout lands further up in the message history.
This issue impacts any user managing long-running conversations, but it is particularly severe in multi-agent workflows (such as a Claude Orchestrator collaborating with local agents). Because these agents generate substantial log activity and multi-turn payloads quickly, the user is forced to manually swipe and scroll down every time they open a thread just to find out what the agents recently decided or output.
## Proposed solution
When a chat thread is opened, the UI list view should instantly anchor and scroll to the absolute bottom of the message stack so the latest information is immediately visible.
Implementing a reversed layout list pattern (standard for iOS messaging interfaces) or triggering an immediate, non-animated scroll-to-bottom on the view's layout pass would ensure a seamless user experience.
## Alternatives considered

* Manual Scrolling: Leaving the UI as-is and requiring the user to swipe down manually. This adds major friction to fast-paced agent interactions.
* A "Scroll to Bottom" Floating Button: Adding a button that appears when the user is scrolled up. While helpful as a secondary feature, it still requires an unnecessary tap upon opening the thread, whereas the initial load should always default to the newest messages.

## Additional context

* Buzz version: 0.5.11
* OS: iOS
* This anchoring issue compounds existing visual sync lags where the user has to kill the session or type a manual message to force a layout mutation. Ensuring the view naturally anchors at the bottom will help keep the state legible.

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If you want, let me know if you would also like me to rewrite your first bug report (the multi-agent silent thread sync issue) into this exact "Motivation / Proposed solution" framework.