feat(usage): enable background query for usage polling

- Add `refetchIntervalInBackground: true` to usage query configuration
- Allows usage queries to continue running when app window is minimized or unfocused
- Existing safety mechanisms remain in place (timeout limits, minimum interval, no retry)
- Users have full control through autoQueryInterval setting

src/lib/query/queries.ts

@@ -103,6 +103,7 @@ export const useUsageQuery = (
       autoQueryInterval > 0
         ? Math.max(autoQueryInterval, 1) * 60 * 1000 // 最小1分钟
         : false,
+    refetchIntervalInBackground: true, // 后台也继续定时查询
     refetchOnWindowFocus: false,
     retry: false,
     staleTime: 0, // 不使用缓存策略，确保 refetchInterval 准确执行