refactor: modularize launcher UI and native services with verified IO

src-tauri/src/commands/preferences.rs

@@ -0,0 +1,24 @@
+use super::data_dir;
+use crate::settings;
+use tauri::AppHandle;
+
+#[tauri::command]
+pub(crate) async fn load_settings(app: AppHandle) -> Result<settings::LauncherSettings, String> {
+    let data_dir = data_dir(&app)?;
+    tauri::async_runtime::spawn_blocking(move || settings::load(&data_dir))
+        .await
+        .map_err(|error| format!("Settings task failed: {error}"))?
+        .map_err(|error| error.to_string())
+}
+
+#[tauri::command]
+pub(crate) async fn save_settings(
+    app: AppHandle,
+    settings: settings::LauncherSettings,
+) -> Result<settings::LauncherSettings, String> {
+    let data_dir = data_dir(&app)?;
+    tauri::async_runtime::spawn_blocking(move || settings::save(&data_dir, settings))
+        .await
+        .map_err(|error| format!("Settings task failed: {error}"))?
+        .map_err(|error| error.to_string())
+}