fix: resolve critical bugs in settings and import flow

Fixed two critical issues:

1. **Blocking Issue - restart_app return type error**
   - Fixed compilation error where restart_app() didn't return a value
   - Used async spawn with 100ms delay to allow response before restart
   - Prevents "unreachable code" compiler error

2. **High Priority - Import SQL doesn't refresh AppSettings cache**
   - Added reload_settings() function to refresh in-memory settings cache
   - Integrated into import flow to ensure imported settings take effect
   - Prevents imported settings being overwritten by stale memory cache
   - Affects: language, config directories, auto-launch, custom endpoints

Changes:
- src/commands/settings.rs: Async delayed restart with proper return value
- src/settings.rs: New reload_settings() to sync memory cache from DB
- src/commands/import_export.rs: Call reload_settings() after SQL import

Verified: cargo clippy --lib and pnpm typecheck both pass

src-tauri/src/commands/import_export.rs

@@ -48,6 +48,11 @@ pub async fn import_config_from_file(
             log::warn!("导入后同步 live 配置失败: {err}");
         }
 
+        // 重新加载设置到内存缓存，确保导入的设置生效
+        if let Err(err) = crate::settings::reload_settings() {
+            log::warn!("导入后重载设置失败: {err}");
+        }
+
         Ok::<_, AppError>(json!({
             "success": true,
             "message": "SQL imported successfully",

src-tauri/src/commands/settings.rs

@@ -18,7 +18,12 @@ pub async fn save_settings(settings: crate::settings::AppSettings) -> Result<boo
 /// 重启应用程序（当 app_config_dir 变更后使用）
 #[tauri::command]
 pub async fn restart_app(app: AppHandle) -> Result<bool, String> {
-    app.restart();
+    // 在后台延迟重启，让函数有时间返回响应
+    tauri::async_runtime::spawn(async move {
+        tokio::time::sleep(tokio::time::Duration::from_millis(100)).await;
+        app.restart();
+    });
+    Ok(true)
 }
 
 /// 获取 app_config_dir 覆盖配置 (从 Store)