feat: 添加使用系统强调色作为主题颜色的样式插件

[Copilot]

• Understand repo structure and plugin system
• Create source file registry/lib/plugins/style/accent-color/index.ts
• Create dist file registry/dist/plugins/style/accent-color.js
• Handle rgba() color format in addition to rgb()
• Add CSS.supports('color', 'AccentColor') guard to prevent fallback color being applied on unsupported browsers
• Fix ESLint errors: use destructuring for getComputedStyle(el).color and add curly braces to if (!match)

[Copilot]

Pull request overview

新增一个样式插件，用系统 CSS 颜色关键字 AccentColor 读取操作系统强调色，并将其同步为 bilibili-evolved 的主题色，以便界面风格与系统主题保持一致。

Changes:

• 新增 style.accentColor 插件：运行时读取系统强调色并写入 themeColor
• 增加对应的预构建 UMD bundle 产物，供 registry 分发使用

Reviewed changes

Copilot reviewed 1 out of 2 changed files in this pull request and generated 1 comment.

File	Description
registry/lib/plugins/style/accent-color/index.ts	插件源码：读取 AccentColor 并设置通用设置的 themeColor
registry/dist/plugins/style/accent-color.js	预构建的 UMD bundle（registry 分发产物）

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[GrassBlock1]

@copilot fix ESLint errors

[Copilot]

@copilot fix ESLint errors

Fixed in f48ed12. Two ESLint errors corrected in index.ts:

• prefer-destructuring: getComputedStyle(el).color → const { color } = getComputedStyle(el)
• curly: added braces to if (!match) { return null }