Clear stagger toast timers on unmount in AnnouncementToastProvider

[MODSetter]

Description

In AnnouncementToastProvider, the useEffect cleanup only clears the outer 1500ms timer. The inner stagger timers (i * 800 per announcement) are never cleared. If the root layout unmounts during the stagger, late toast calls fire after cleanup.

File to change

• surfsense_web/components/announcements/AnnouncementToastProvider.tsx (lines 64-82)

Current code

useEffect(() => {
  if (hasChecked.current) return;
  hasChecked.current = true;

  const timer = setTimeout(() => {
    // ...
    for (let i = 0; i < importantUntoasted.length; i++) {
      const announcement = importantUntoasted[i];
      setTimeout(() => showAnnouncementToast(announcement), i * 800); // Not tracked!
    }
  }, 1500);

  return () => clearTimeout(timer); // Only clears outer timer
}, []);

What to do

Track inner timer IDs and clear all in cleanup:

useEffect(() => {
  if (hasChecked.current) return;
  hasChecked.current = true;
  const timerIds: ReturnType<typeof setTimeout>[] = [];

  const outerTimer = setTimeout(() => {
    // ...
    for (let i = 0; i < importantUntoasted.length; i++) {
      const announcement = importantUntoasted[i];
      timerIds.push(
        setTimeout(() => showAnnouncementToast(announcement), i * 800)
      );
    }
  }, 1500);

  return () => {
    clearTimeout(outerTimer);
    timerIds.forEach(clearTimeout);
  };
}, []);

Acceptance criteria

• All stagger timers are cleared on cleanup
• Announcement toasts still appear with staggered timing on normal flow

[mac-agent]

PR #1132 addresses this — added cleanup for the stagger timers inside the for loop. Both the outer timer and all inner stagger timers are now cleared on unmount.

[JiwaniZakir]

The root cause is that the inner setTimeout calls inside the outer 1500ms callback are fire-and-forget — their IDs are never stored, so the useEffect cleanup has no way to cancel them. If the component unmounts during the stagger window (e.g., a route change between 1500ms and 1500ms + n * 800ms), the pending showAnnouncementToast calls still execute against an unmounted tree. In AnnouncementToastProvider.tsx around lines 64–82, the fix is to collect the inner timer IDs into an array (initialized before the outer setTimeout so it's in the cleanup closure's scope) and iterate clearTimeout over them in the return callback alongside clearTimeout(outerTimer). Worth noting: hasChecked.current being set before the timers fire means a remount won't re-trigger the effect, but that doesn't help with the in-flight timers from the original mount.