GitHub web UI lacks visible navigation to commit history

### Issue

The GitHub.com web interface does not provide an obvious or easily discoverable link to view a repository's commit history from the main repository page. Users looking to see contributions or recent changes must either:
- Know and type the direct URL manually (e.g., `/commits`)
- Search through sidebar menus
- Use keyboard shortcuts or browser find functions

### Context

When attempting to find how to view all contributions to a repository through the standard GitHub UI, there is no clear "Commits" or "History" button or link in the main header navigation or file browser area. This discoverability issue affects user experience, particularly for those new to GitHub or unfamiliar with direct URL navigation patterns.

### Expected Behavior

A clearly visible link or button (labeled "Commits," "History," or similar) should be accessible from:
- The main repository navigation header
- The file browser area
- Or prominently displayed in the repository sidebar

This would allow users to quickly access commit history without extra effort or knowledge of GitHub's URL structure.

### Additional Notes

- Encountered while using GitHub's Copilot Chat interface
- May impact user onboarding and general repository navigation
- Related to overall UI/UX design of the repository view

未指定任何仓库文件或测试。首先确认此仓库是否能够修改 GitHub.com 的 UI，然后检查报告中所描述的仓库导航标题、文件浏览区域和侧边栏。完成的标准是在适当的项目中定义并实现一条通往提交历史的、可见且易于发现的路径。

由索引模型根据 Issue 内容生成。