fix(extension): add window focus change detection to lace tab activity check (#2010)

1.	The Service Worker (SW) exposes an observable isLaceTabActive$,
	which reports changes when:
	•	a window is closed
	•	a tab is updated (URL changes)
	•	a tab is activated (user switches tabs)
	2.	The UI subscribes to this observable.
	3.	After ~30 seconds of inactivity, Chrome suspends the SW due to lack of focus.
	4.	When the UI resubscribes to isLaceTabActive$ after the SW was suspended:
	•	The observable restarts with its startWith value (false).
	•	Because the SW was suspended, no tab events (from step 1) have fired,
	so nothing updates the observable.
	•	As a result, the UI keeps seeing false and shows “Blockchain out of sync.”
	5.	Returning to the tab does not fix the issue because no event is triggered
	to flip isLaceTabActive$ back to true.
	6.	Clicking the menus works because trigger navigation changes so the tab.onUpdated event fires,
	which updates isLaceTabActive$ to true.

⸻

Solution
	•	The SW should also monitor the windowFocusChanged$ event.
	•	When the window regains focus, the event will fire, the observable
	emits true if the tab is still open	which tells the UI it is safe to resume communication.

Author: mirceahasegan

apps/browser-extension-wallet/src/lib/scripts/background/session/is-lace-tab-active.ts

@@ -8,6 +8,12 @@ const windowRemoved$ = fromEventPattern<WindowId>(
   (handler) => windows.onRemoved.addListener(handler),
   (handler) => windows.onRemoved.removeListener(handler)
 );
+
+const windowFocusChanged$ = fromEventPattern<WindowId>(
+  (handler) => windows.onFocusChanged.addListener(handler),
+  (handler) => windows.onFocusChanged.removeListener(handler)
+);
+
 const tabUpdated$ = fromEventPattern(
   (handler) => tabs.onUpdated.addListener(handler),
   (handler) => tabs.onUpdated.removeListener(handler),
@@ -30,7 +36,7 @@ const getExtensionTabUrlPattern = () => {
   return `${url.origin}/*`;
 };
 
-export const isLaceTabActive$ = merge(windowRemoved$, tabUpdated$, tabActivated$).pipe(
+export const isLaceTabActive$ = merge(windowRemoved$, tabUpdated$, tabActivated$, windowFocusChanged$).pipe(
   switchMap(() =>
     from(
       catchAndBrandExtensionApiError(