feat(updater): 集成 Rust 侧 Updater/Process 插件与权限配置

- Cargo 依赖：tauri-plugin-updater、tauri-plugin-process
- 插件注册：process 顶层 init，updater 于 setup 中注册
- 权限配置：capabilities 增加 updater:default、process:allow-restart
- 配置：tauri.conf.json 启用 createUpdaterArtifacts 与 updater 占位（pubkey/endpoints）

src-tauri/Cargo.toml

@@ -24,6 +24,8 @@ log = "0.4"
 tauri = { version = "2.8.2", features = ["tray-icon"] }
 tauri-plugin-log = "2"
 tauri-plugin-opener = "2"
+tauri-plugin-process = "2"
+tauri-plugin-updater = "2"
 dirs = "5.0"
 toml = "0.8"