🦄 refactor: 重写本地扫描逻辑

[apoint123]

再次重写了本地扫描的逻辑，主要把原生代码从媒体控件的crate移动到了工具crate；删掉了LocalMusicService.ts里面大部分功能和原生模块重合的代码；还有一些性能改善

[gemini-code-assist]

Summary of Changes

Hello @apoint123, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

此拉取请求显著重构了本地音乐扫描机制。之前基于 JavaScript 的扫描逻辑（涉及 music-metadata 和 FastGlob）已被高度优化的原生 Rust 实现取代。这一更改将文件遍历、元数据解析和封面提取等 CPU 密集型任务转移到一个专门的 tools Rust crate，利用并行处理来提高性能。JavaScript 端现在充当协调器，启动原生扫描并接收流式更新，从而在库同步期间提供更高效、响应更快的用户体验。

Highlights

• 本地扫描逻辑重构: 将本地音乐扫描、元数据解析和封面提取的核心逻辑完全重写为 Rust，并从 external-media-integration crate 迁移到一个新的 tools crate。
• 性能优化: 通过将 CPU 密集型的文件 I/O 和元数据解析任务卸载到使用并行处理 (rayon) 的原生 Rust 模块，扫描过程预计将显著加快并提高效率。
• 简化 JavaScript 逻辑: Electron 主进程中的 LocalMusicService.ts 已被简化，不再直接处理文件遍历、元数据解析或封面提取，而是将这些任务委托给原生 tools 模块，并通过回调接收更新（进度、批量音轨、已删除路径）。
• 数据库交互: 原生 Rust 模块现在直接与 SQLite 数据库交互，以加载现有音轨快照、确定哪些文件需要重新处理以及识别已删除的文件。
• 封面处理: 封面提取和大小调整现在在 Rust 模块内部使用 image crate 处理，并保存为 JPG 格式。
• IPC 通信更新: 音乐扫描的 IPC 通信已更新为支持流式传输方法，原生模块将进度更新和批量音轨发送到渲染器进程，最后发送完成信号。渲染器端 (layout.vue) 已适应处理这种新的流式数据。

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[gemini-code-assist]

Code Review

本次重构将本地音乐扫描逻辑迁移到了 Rust 原生模块，这是一个很好的性能优化方向。代码结构更加清晰，将耗时的文件I/O和解析操作放到了后台线程中执行，避免了对主进程的阻塞。我发现了一些可以改进的地方，主要集中在数据流处理和原生代码的健壮性方面。具体请看我的详细评论。