Add patch/diff file visualization extension with diff2html

[Copilot]

VSCode extension for visualizing .patch and .diff files with diff2html, providing two-tab editing and theme-aware rendering.

Changes

Extension Core

• Custom Editor Provider (src/patchEditorProvider.ts): Webview-based editor with two tabs—Visual Diff (diff2html rendered) and Raw Content
• View Modes: Side-by-side and unified toggle with persisted preference
• Theme Integration: Follows VSCode theme (Light/Dark/High Contrast) via onDidChangeActiveColorTheme, auto-refreshes on switch
• Auto-render: Content changes trigger immediate re-render

Configuration

• tlcsdm.patchReader.defaultViewMode: Default view mode setting (side-by-side | unified)
• Command: tlcsdm.patchReader.toggleView for programmatic view switching

Internationalization

• English (default), Chinese (zh-cn), and Japanese (ja) language support
• Localized strings in package.nls.json, package.nls.zh-cn.json, package.nls.ja.json

Project Structure

• GitHub workflows: build.yml, artifact.yml, publish.yml, release.yml, sync-gitee.yml
• dependabot.yml for npm and GitHub Actions updates
• CODEOWNERS for review routing
• Standard VSCode extension scaffolding (tsconfig, eslint, .vscodeignore)
• Extension icon at images/icon.png

Accessibility

• ARIA attributes on tabs (role="tab", aria-selected) and view toggles (aria-pressed)
• Proper tabpanel associations with aria-labelledby

Usage

// Opens automatically for .patch/.diff files
// Or configure default view mode:
{
  "tlcsdm.patchReader.defaultViewMode": "unified"
}

Original prompt

---

This section details on the original issue you should resolve

<issue_title>需求</issue_title>
<issue_description>1. vscode插件结构可以参考 我的别的项目，比如 https://github.com/tlcsdm/vscode-java-method-sorter
2. 主分支master
3. 提供.github 下dependabot,codeowner 工作流参考vscode-java-method-sorter
4. 具体功能可以参考https://github.com/tlcsdm/patchReader-extension
实现一个patch和diff文件的可视化插件，在打开patch和diff文件时提供两个tab
第一个tab是利用diff2html可视化，第二个tab显示原本的内容
在修改内容后自动渲染第一个tab
渲染的diff2html UI主题(Light/Dark)跟整个vscode主题走, 如果切换vscode主题，第一个tab的颜色主题也要刷新
提供SidebySide和Unified视图切换
</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes 需求 #1

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[unknowIfGuestInDream]

@copilot

1. 缺少images/icon.png
2. 支持国际化 (中日英) 默认英文
3. Installation 添加从jenkins获取的信息
4. README中 Setup 去掉 clone步骤，去掉Project Structure
5. README中引用的images不存在

[Copilot]

@copilot

1. 缺少images/icon.png
2. 支持国际化 (中日英) 默认英文
   ...

Addressed in dc48618:

1. Added images/icon.png
2. Added i18n support with package.nls.json (English default), package.nls.zh-cn.json (Chinese), package.nls.ja.json (Japanese)
3. Added Jenkins installation section in README
4. Removed clone step and Project Structure from README
5. Removed non-existent image references (Screenshots section) from README