feat: implement auto scroll

components/chat-scroll-anchor.tsx

@@ -0,0 +1,29 @@
+'use client'
+
+import * as React from 'react'
+import { useInView } from 'react-intersection-observer'
+
+import { useAtBottom } from '@/lib/hooks/use-at-bottom'
+
+interface ChatScrollAnchorProps {
+  trackVisibility?: boolean
+}
+
+export function ChatScrollAnchor({ trackVisibility }: ChatScrollAnchorProps) {
+  const isAtBottom = useAtBottom()
+  const { ref, entry, inView } = useInView({
+    trackVisibility,
+    delay: 100,
+    rootMargin: '0px 0px -150px 0px'
+  })
+
+  React.useEffect(() => {
+    if (isAtBottom && trackVisibility && !inView) {
+      entry?.target.scrollIntoView({
+        block: 'start'
+      })
+    }
+  }, [inView, entry, isAtBottom, trackVisibility])
+
+  return <div ref={ref} className="h-px w-full" />
+}