:lightning: optimize chat streaming

src/renderer/components/AIChat/ChatMessageItem.tsx

@@ -1,4 +1,4 @@
-import { useMemo } from 'react'
+import { useMemo, memo } from 'react'
 import { marked } from 'marked'
 import DOMPurify from 'dompurify'
 import type { ChatMessage, TextAnnotation } from '../../types/editor'
@@ -30,7 +30,7 @@ interface Props {
   linkedAnnotations?: TextAnnotation[]
 }
 
-export function ChatMessageItem({ message, linkedAnnotations }: Props): JSX.Element {
+function ChatMessageItemInner({ message, linkedAnnotations }: Props): JSX.Element {
   const { activeFilePath, markSaved } = useEditorStore()
 
   const html = useMemo(() => {
@@ -123,3 +123,13 @@ export function ChatMessageItem({ message, linkedAnnotations }: Props): JSX.Elem
     </div>
   )
 }
+
+function areEqual(prev: Props, next: Props): boolean {
+  if (prev.message.content !== next.message.content) return false
+  if (prev.message.id !== next.message.id) return false
+  const prevIds = prev.linkedAnnotations?.map(a => a.id).join(',') ?? ''
+  const nextIds = next.linkedAnnotations?.map(a => a.id).join(',') ?? ''
+  return prevIds === nextIds
+}
+
+export const ChatMessageItem = memo(ChatMessageItemInner, areEqual)

src/renderer/components/AIChat/ChatPanel.tsx

@@ -50,6 +50,7 @@ export function ChatPanel(): JSX.Element {
   const [pendingAttachmentCount, setPendingAttachmentCount] = useState(0)
   const [feedbackNotice, setFeedbackNotice] = useState<string | null>(null)
   const scrollRef = useRef<HTMLDivElement>(null)
+  const scrollRafRef = useRef<number | null>(null)
   const prevAnnotationCountRef = useRef(annotations.length)
 
   // Collapse history when switching files
@@ -119,12 +120,14 @@ export function ChatPanel(): JSX.Element {
     }
   }
 
-  // Auto-scroll to bottom when new content arrives
+  // Auto-scroll to bottom when new content arrives (coalesced to one scroll per animation frame)
   useEffect(() => {
-    const el = scrollRef.current
-    if (el) {
-      el.scrollTop = el.scrollHeight
-    }
+    if (scrollRafRef.current !== null) return
+    scrollRafRef.current = requestAnimationFrame(() => {
+      scrollRafRef.current = null
+      const el = scrollRef.current
+      if (el) el.scrollTop = el.scrollHeight
+    })
   }, [chatHistory])
 
   const hasFile = Boolean(activeFilePath)