feat: scroll chat to bottom when user submits a new message

[0xenzyme]

What

Adds an explicit animated scroll-to-end call inside "onSend" so the chat transcript scrolls to the bottom immediately when a user submits a new message.

Why

Previously, scrolling to the bottom after sending a message relied on the "transcriptMessageCount" useEffect firing only when the user was already at the end of the transcript. If the user scrolled up and then sent a message, the transcript would stay out of view. This change makes the scroll explicit and immediate.

How

• In "ChatView.tsx" onSend, after inserting the optimistic user message and resetting the anchor state, we now call "window.requestAnimationFrame(() => scrollToEnd(true))" to trigger an animated scroll to the bottom.
• Also marks the corresponding TODO item as complete.

Verification

• bun fmt ✅
• bun lint ✅ (no new issues)
• bun typecheck ✅ (8/8 packages pass)

[jwangkun]

PR 审查报告

结论：需修改 ✗ 暂不可合并

审查摘要

维度	结果	说明
问题修复	⚠️ 存疑	现有 useEffect 在 transcriptMessageCount 变化时已处理滚动，理论上无需此修改
代码规范	✗ bun.lock 有大问题	registry URL 全部改为 npmmirror.com，锁文件完整性被破坏
与项目方向对齐	⚠️ 部分对齐	但 bun.lock + 无关格式化噪声污染了 PR

详细分析

问题 1（阻塞）：bun.lock registry URL 全部变更 ✗

- "@anthropic-ai/claude-agent-sdk": ["@anthropic-ai/claude-agent-sdk@0.2.112", "", { ...
+ "@anthropic-ai/claude-agent-sdk": ["@anthropic-ai/claude-agent-sdk@0.2.112", "https://registry.npmmirror.com/...", { ...

bun.lock 中所有包的 registry URL 从 "" 被改为了 https://registry.npmmirror.com/...，共 1300+ 行。这是运行 bun install 时使用了非默认 registry 造成的，不属于 PR 的意图。此变更会破坏其他开发者的构建环境。必须还原到 main 分支版本。

问题 2（建议）：3 个无关文件的纯格式化变更

• ProviderHealth.ts — 纯换行格式变更
• BrowserPanel.tsx — 纯换行格式变更
• git.ts — 纯换行格式变更

与 PR 主题无关，属于 bun fmt 的适用范围，应移除或拆分为独立 PR。

问题 3（讨论）：核心修改是否真的修复了问题？

当前代码（PR 前的 ChatView.tsx）中：

1. onSend 在 line 5567 已设置 isAtEndRef.current = true
2. useEffect 监听 transcriptMessageCount（line 3955），变化时调用 scrollToEnd(false)
3. timelineMessages（line 2188）包含 optimisticUserMessages，因此新消息会正确触发 count 变化

所以用户在滚动后发送消息时，流程是：
isAtEndRef.current = true → 状态更新 → useEffect 触发 → scrollToEnd(false)

现有代码理论上已经正确处理了该场景。 PR 添加的 requestAnimationFrame(() => scrollToEnd(true)) 并非 bugfix，而是一个额外行为（动画 & 更早的调度时机）。虽然无害，但建议 PR 描述中明确说明这是增强而非 修复。

合并前必须修复

1. 还原 bun.lock 到 main 版本（git checkout main -- bun.lock）
2. 移除 ProviderHealth.ts / BrowserPanel.tsx / git.ts 的格式化变更（这些是 pre-existing 的 fmt 漂移）

按 AGENTS.md 要求，验证结果：

• bun fmt:check ✅
• bun typecheck ✅
• bun lint ✅
• bun run test ✅（ChatMarkdown test 为 pre-existing 问题）

[jwangkun]

PR Closed — Stale\n\nHi @0xenzyme, thank you for your contribution.\n\nThis PR has been closed because PR is unvouched and oversized (XXL) per project guidelines.\n\n### Next steps\n- If you'd like to continue working on this, please address the review feedback and re-open the PR or open a new one.\n- For new features, please start a Discussion first to align with the project direction.\n- Keep PRs small, focused, and well-described per our template.\n\nFeel free to reach out if you have questions!