修复纯聊天流式回复滚动

恢复 standalone supervisor 聊天的流式消息自动跟随
保留用户上移后的滚动位置
统一使用底部阈值判断是否继续跟随

apps/ai-game-creator-shell/src/features/project-workspace/SupervisorChatOnlyView.tsx

@@ -5,8 +5,10 @@ import type {
   FormEventHandler,
   RefObject,
   SetStateAction,
+  UIEvent,
   UIEventHandler,
 } from 'react';
+import { useLayoutEffect, useRef } from 'react';
 
 import type {
   AgentRuntimeState,
@@ -33,6 +35,8 @@ type RuntimeControlProps = ComponentProps<
   typeof ProjectSupervisorRuntimeControls
 >;
 
+const CHAT_SCROLL_BOTTOM_THRESHOLD = 24;
+
 type SupervisorChatOnlyViewProps = {
   chatAgentBusy: boolean;
   chatInput: string;
@@ -95,6 +99,7 @@ export function SupervisorChatOnlyView({
   visibleMessages,
   workspaceStatus,
 }: SupervisorChatOnlyViewProps) {
+  const shouldFollowLatestRef = useRef(true);
   const running = Boolean(
     chatAgentBusy || (runtime && !isAgentRuntimeTerminalState(runtime)),
   );
@@ -107,6 +112,34 @@ export function SupervisorChatOnlyView({
     : runtime
       ? projectSupervisorChatRuntimeStatus(runtime)
       : projectWorkspaceStatusForDisplay(workspaceStatus);
+  useLayoutEffect(() => {
+    if (!running) {
+      return;
+    }
+    const messageList = messagesRef.current;
+    if (!messageList) {
+      return;
+    }
+    if (shouldFollowLatestRef.current) {
+      messageList.scrollTop = messageList.scrollHeight;
+    }
+  }, [
+    messagesRef,
+    running,
+    runtime?.updatedAt,
+    transientReply,
+    visibleMessages.length,
+  ]);
+  function handleScroll(event: UIEvent<HTMLDivElement>) {
+    const messageList = event.currentTarget;
+    const distanceFromBottom =
+      messageList.scrollHeight -
+      messageList.scrollTop -
+      messageList.clientHeight;
+    shouldFollowLatestRef.current =
+      distanceFromBottom <= CHAT_SCROLL_BOTTOM_THRESHOLD;
+    onScroll(event);
+  }
   const conversationLabel = directCodex
     ? '陶泥儿项目对话'
     : '项目总控 Agent 纯聊天';
@@ -139,7 +172,7 @@ export function SupervisorChatOnlyView({
           ref={messagesRef}
           className="message-list supervisor-chat-only-message-list"
           aria-label={directCodex ? '陶泥儿消息' : '项目总控消息'}
-          onScroll={onScroll}
+          onScroll={handleScroll}
         >
           {hiddenConversationCount > 0 ? (
             <button