Convert Uptime Kuma, Paperless-ngx, audio-stats, and UPS widgets to use useQuery with WidgetEmptyState fallback, consistent with the query cache persistence pattern from PR #5811.
Convert Uptime Kuma, Paperless-ngx, audio-stats, and UPS widgets to use useQuery with WidgetEmptyState fallback, consistent with the query cache persistence pattern from PR #5811.