Fix background not covering safe area in dark mode

[Copilot]

Absolutely positioned backgrounds were constrained by SafeAreaProvider boundaries, causing white borders at screen edges in dark mode (particularly bottom safe area on ColorOS 15).

Changes

• Added useBackgroundInsets hook - Returns negative safe area insets to extend backgrounds beyond safe boundaries
• Updated PageBackground component - Applied hook to cover home/drawer backgrounds
• Updated MusicDetail background - Applied same pattern for consistency

Implementation

// New hook
export default function useBackgroundInsets() {
    const insets = useSafeAreaInsets();
    return {
        top: -insets.top,
        bottom: -insets.bottom,
        left: -insets.left,
        right: -insets.right,
    };
}

// Usage in background components
const backgroundInsets = useBackgroundInsets();
<View style={[style.background, backgroundInsets]} />

Interactive content remains properly inset via existing SafeAreaView components with edges configuration.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• registry.npmmirror.com
  • Triggering command: /usr/local/bin/node node /usr/local/bin/npm install (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

---

This section details on the original issue you should resolve

<issue_title>背景未完全覆盖</issue_title>
<issue_description>### 提问题之前，请先确认

• 已经阅读过Q&A (https://musicfree.catcat.work/qa/mobile.html)
• 要提出的问题与插件功能无关（类似某个插件搜索结果不全、ip被封禁等请找对应插件作者，在此仓库下提具体插件的问题将会被直接关闭）
• 不与其他已有issue重复

系统信息

0.6.3-beta.0
coloros15

问题描述

背景底有未被覆盖的白边。打开菜单其背景显示正常，可以确定非手势条

复现步骤

主题选择深色模式

截图 & 日志

</issue_description>

<agent_instructions>This issue is related to SafeArea. Please fix this issue. Make sure your change won't affect existing functions.</agent_instructions>

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

• Fixes 背景未完全覆盖 #544

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.