When one or more batch chunks fail (e.g., a transient network error), only the successful chunks contribute to `mergedMetrics`, while the Zustand store's `setMetrics` merges the partial result into existing state (`{ ...state.metrics, ...metrics }`), leaving sandbox IDs from the failed chunk with their previous stale values indefinitely. The UI then silently displays a mixed-freshness table—some rows current, others outdated—with no error or loading indicator to alert the user. Before this PR a 

The new `useQueries` call returns a new array reference on every render (without `combine`), so `useMemo([queryResults])` recomputes `mergedMetrics` every render cycle—even when fetched data is unchanged. This causes `useEffect` to fire and `setMetrics` to be called on every render, which updates the Zustand store and re-renders all sandbox metric cells on every polling interval. The fix is to add a `combine` option to `useQueries` that merges results into a stable object, so downstream dependen