refactor(types): introduce Settings and apply in API

- style(prettier): format src files
- style(rustfmt): format Rust sources
- refactor(tauri-api): type-safe getSettings/saveSettings
- refactor(d.ts): declare window.api with Settings

[skip ci]

src/types.ts

@@ -9,3 +9,8 @@ export interface AppConfig {
   providers: Record<string, Provider>;
   current: string;
 }
+
+// 应用设置类型（用于 SettingsModal 与 Tauri API）
+export interface Settings {
+  showInDock: boolean;
+}