manageSubscription fails with useIntersectionObserver and GridLayout

### Select which package(s) are affected \@livekit/components-react ### Describe the bug ### What I'm expecting When` manageSubscription` is enabled on VideoTrack, track subscription should follow tile visibility consistently: 1. **subscribe** when the tile becomes visible 2. **unsubscribe** when the tile is no longer visible (including GridLayout page changes where tiles are removed from the DOM) ### What happens instead `manageSubscription` is unreliable in two cases: - after the usehooks-ts v3 migration I guess, `useIntersectionObserver` was not wired correctly, so visibility updates (`intersectionEntry?.isIntersecting`) were not consistently reflected - with GridLayout pagination, tiles are unmounted when leaving the page, and no intersection “exit” event is fired, so unsubscribe may not happen as expected ### Reproduction 1. Render participant videos with `manageSubscription={true}` on **VideoTrack**. 2. Use both layouts: - **GridLayout** with enough participants to enable pagination - **CarouselLayout** with scroll 3. Add logs for: - `intersectionEntry?.isIntersecting`, - calls to `publication.setSubscribed(...)` 4. In CarouselLayout, scroll tiles in/out of view 5. In GridLayout, switch pages so tiles are removed from DOM ### Observed `intersectionEntry?.isIntersecting` is not reliable (always false), so visibility-based subscription logic does not behave as expected. In GridLayout pagination, tiles can unmount without a usable visibility transition, so unsubscribe is missed if only driven by intersection updates. ### Expected `isIntersecting` should correctly reflect tile visibility changes. With `manageSubscription`, tracks should subscribe when visible and unsubscribe when hidden or unmounted (including grid page changes). ### Logs ```shell ``` ### System Info ```shell Package: @livekit/components-react Version: 2.9.20 Browsers: Chrome, Firefox OS: Windows 1 Node.js: 24 ``` ### Severity annoyance ### Additional Information _No response_