refactor: 清理未使用依赖与配置，精简项目结构

- 移除不必要的权限配置opener:default
- 移除不再使用的异步相关依赖项及其实现，精简项目依赖树。
- 移除未使用的 tauri-plugin-opener 依赖项
- 移除已弃用的 tauri_plugin_opener 插件初始化，保留 shell 插件初始化并注册全局状态

Cargo.toml

@@ -19,7 +19,6 @@ tauri-build = { version = "2", features = [] }
 
 [dependencies]
 tauri = { version = "2", features = [] }
-tauri-plugin-opener = "2"
 tauri-plugin-shell = "2"
 serde = { version = "1", features = ["derive"] }
 tokio = { version = "1", features = ["net"] }