feat: 添加二维码生成功能并简化架构

- 新增二维码生成服务层，支持自定义内容和配置
  - 移除 Platform 抽象层，简化为三层架构
  - 更新开发文档和架构说明
  - 添加前端二维码生成页面和状态管理

src-tauri/Cargo.toml

@@ -24,6 +24,9 @@ tauri-plugin-global-shortcut = "2"
 serde = { version = "1", features = ["derive"] }
 serde_json = { version = "1", features = ["preserve_order"] }
 sysinfo = "0.30"
+qrcode = "0.14"
+image = "0.25"
+base64 = "0.22"
 
 [target.'cfg(windows)'.dependencies]
 windows = { version = "0.58", features = [