fix(react): guard processor cast and detach on unmount

Two correctness fixes from PR review:

- Guard the `KrispNoiseFilterProcessor` cast in the returned `processor`
  value with the same `name === 'livekit-noise-filter'` check used
  inside the effect. The unconditional cast assumed nothing else could
  attach a `TrackProcessor` to the track; if anything did, the hook
  handed consumers a value typed as a Krisp processor that wasn't one.

- Add an unmount-only effect that detaches the Krisp processor from
  the currently-managed track. Empty deps so it doesn't interfere with
  the existing toggle-reuse path on shouldEnable / filterOptions / track
  changes. Closes the gap where a caller-owned `trackRef` outlives the
  hook's component, leaving the track with a Krisp processor attached
  that the hook no longer manages.

Author: Topherhindman

packages/react/src/hooks/cloud/krisp/useKrispNoiseFilter.ts

@@ -48,6 +48,13 @@ export function useKrispNoiseFilter(options: useKrispNoiseFilterOptions = {}) {
     micPublication = options.trackRef.publication;
   }
 
+  // Holds the LocalAudioTrack the hook is currently managing, so the unmount
+  // cleanup below can detach the Krisp processor even when a caller-owned
+  // trackRef outlives this component.
+  const managedTrackRef = React.useRef<LocalAudioTrack | undefined>(undefined);
+  managedTrackRef.current =
+    micPublication?.track instanceof LocalAudioTrack ? micPublication.track : undefined;
+
   const setNoiseFilterEnabled = React.useCallback(async (enable: boolean) => {
     if (enable) {
       const { isKrispNoiseFilterSupported } = await import('@livekit/krisp-noise-filter');
@@ -126,9 +133,32 @@ export function useKrispNoiseFilter(options: useKrispNoiseFilterOptions = {}) {
     };
   }, [shouldEnable, micPublication?.track, options.filterOptions]);
 
-  const processor =
+  // Detach on unmount. Empty deps mean the cleanup only fires when the hook
+  // unmounts, not on every track / shouldEnable / filterOptions change — so it
+  // doesn't interfere with the toggle-reuse path above. Covers the case where
+  // a caller-owned trackRef outlives the hook's component.
+  React.useEffect(() => {
+    return () => {
+      const track = managedTrackRef.current;
+      if (!track) return;
+      if (track.getProcessor()?.name !== 'livekit-noise-filter') return;
+      // Fire-and-forget: cleanup can't await. stopProcessor is a no-op when
+      // the track was already stopped externally (e.g. on Room disconnect).
+      track.stopProcessor().catch((e) => {
+        log.warn('Krisp hook: error detaching processor on unmount', e);
+      });
+    };
+  }, []);
+
+  const trackProcessor =
     micPublication?.track instanceof LocalAudioTrack
-      ? (micPublication.track.getProcessor() as KrispNoiseFilterProcessor | undefined)
+      ? micPublication.track.getProcessor()
+      : undefined;
+  // Guard the cast: another module could have set a non-Krisp processor on the
+  // track, and we should not lie to consumers about its type.
+  const processor =
+    trackProcessor?.name === 'livekit-noise-filter'
+      ? (trackProcessor as KrispNoiseFilterProcessor)
       : undefined;
 
   return {