Improve chat UX with scroll and padding fixes (#99)

* fix: improve chat UX with better scroll and symmetric padding

- Add alignToBottom prop to Virtuoso for better last message visibility
- Add small footer to prevent last message from being hidden under scroll
- Make composer padding symmetric (py-1 instead of py-1 pb-0)

* fix: restore pb-0 on composer

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Co-authored-by: Claude <noreply@anthropic.com>

src/components/ChatViewer.tsx

@@ -836,6 +836,7 @@ export function ChatViewer({
             data={messagesWithMarkers}
             initialTopMostItemIndex={messagesWithMarkers.length - 1}
             followOutput="smooth"
+            alignToBottom
             components={{
               Header: () =>
                 hasMore && conversationResult.status === "success" ? (
@@ -857,6 +858,7 @@ export function ChatViewer({
                     </Button>
                   </div>
                 ) : null,
+              Footer: () => <div className="h-1" />,
             }}
             itemContent={(_index, item) => {
               if (item.type === "day-marker") {