gacor: Pause unnecessary work when a page becomes hidden

A page left open in a background tab may not need to keep animating or refreshing non-critical data. The visibilitychange event lets an application pause optional work when the document is hidden and resume it when visible.

function updateActivity() {
  if (document.hidden) {
    stopOptionalPolling();
    return;
  }
  refreshVisibleData();
}

document.addEventListener("visibilitychange", updateActivity);
updateActivity();

Pause only work that can safely wait

• Keep essential persistence and user-triggered operations reliable regardless of tab visibility.
• Resume with a fresh state check instead of assuming every missed timer ran.
• Remove the event listener when the page-level controller is disposed.

Background timers are already throttled differently across browsers. Treat visibility as a signal to reduce optional work, not as a precise scheduling mechanism.

Test by switching tabs and returning after a delay. The interface should refresh from current state without duplicating a request or losing user input.