openclaw - 💡(How to fix) Fix [Scroll UX] 流式回复自动滚动导致阅读焦点丢失 / Auto-scroll during streaming causes focus loss while reading

问题描述 / Issue Description

在与 OpenClaw Control UI / WebChat 对话时，AI 流式回复（token by token）会持续撑高消息区域，页面自动跟随最新内容滚动到底部。用户如果正在阅读回复上方的内容，阅读焦点会被新内容"顶下去"，需要频繁手动向上滚动以恢复阅读位置。

When chatting with OpenClaw Control UI / WebChat, the streaming response (generated token by token) continuously grows the message area, and the viewport auto-scrolls to the bottom to follow new content. If the user is reading earlier parts of the response above, their reading focus is pushed out of view and they must manually scroll back up repeatedly.

根本原因 / Root Cause

前端在内容更新时始终将 scrollTop 锚定在 scrollHeight，没有检测用户当前滚动位置。

The frontend always anchors scrollTop to scrollHeight on content update, without checking the user`s current scroll position.

期望行为 / Expected Behavior

• 仅在用户已在底部时自动跟随新内容。 若用户正在向上滚动阅读，保持当前视口位置不动。
• Auto-follow new content only when the user is already at the bottom. If the user has scrolled up to read earlier content, preserve the current viewport position.

类似 Discord, Slack, Telegram 等 IM 应用中通用的"智能滚动"行为： Similar to the "smart scroll" behavior in apps like Discord, Slack, and Telegram:

• 用户在底部 → 自动跟随新消息
• User at bottom → auto-scroll follows new content
• 用户滚上去阅读 → 不打断，保持当前位置
• User scrolled up reading → do not interrupt, stay at current position

影响范围 / Affected

• Control UI / WebChat 消息渲染区域
• Control UI / WebChat message rendering area

环境 / Environment

• OpenClaw (Homebrew)
• macOS (Darwin arm64)
• WebChat / direct conversation