fix(lotus): screenshare-audio mute survives a re-share — mute via the renderer, not setVolume

"Mute Screenshare Audio" (io.lotus.set_deafen screenshareAudioMuted) used
RemoteParticipant.setVolume(0, ScreenShareAudio). EC's own createVolumeControls
writes volume 1 through the same setter the moment a new screenshare media item
resolves, so when the sharer stopped and re-shared (or a late joiner shared)
the audio came back at full volume while the host button still said
"Unmute Screenshare Audio". Reproduced on the local calls stack with two
headless clients: after a re-share the screen_share_audio element read vol=1.

Now the flag is a global behavior (muteScreenshareAudio$) that
LivekitRoomAudioRenderer turns into the `muted` prop of every
Track.Source.ScreenShareAudio element — the exact mechanism deafen already uses
(pub.setEnabled(false): the server stops sending). Verified via the
RemoteTrackPublication behind each <audio>: the re-published track (new sid)
mounts with enabled=false while muted and re-enables on unmute; deafen +
undeafen leaves it muted; teardown resets the flag so the next call starts
clean. Unit tests updated; renderer test asserts only ScreenShareAudio
elements get muted by the new prop.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

src/livekit/MatrixAudioRenderer.test.tsx

@@ -52,9 +52,16 @@ afterEach(() => {
 vi.mock("@livekit/components-react", async (importOriginal) => {
   return {
     ...(await importOriginal()),
-    AudioTrack: (props: { trackRef: TrackReference }): ReactNode => {
+    AudioTrack: (props: {
+      trackRef: TrackReference;
+      muted?: boolean;
+    }): ReactNode => {
       return (
-        <audio data-testid={"audio"}>
+        <audio
+          data-testid={"audio"}
+          data-source={props.trackRef.publication.source}
+          data-muted={String(!!props.muted)}
+        >
           {getTrackReferenceId(props.trackRef)}
         </audio>
       );
@@ -83,6 +90,7 @@ function renderTestComponent(
     kind: Track.Kind;
     source: Track.Source;
   }[],
+  props: { muted?: boolean; screenshareAudioMuted?: boolean } = {},
 ): RenderResult {
   const liveKitParticipants = livekitParticipantIdentities.map((identity) =>
     mockRemoteParticipant({ identity }),
@@ -117,6 +125,7 @@ function renderTestComponent(
         validIdentities={participants.map((p) => p.identity)}
         livekitRoom={livekitRoom}
         url={""}
+        {...props}
       />
     </MediaDevicesProvider>,
   );
@@ -286,3 +295,55 @@ it("should setup audioContext gain and pan", () => {
   expect(testAudioContext.gain.gain.value).toEqual(0.1);
   expect(testAudioContext.pan.pan.value).toEqual(1);
 });
+
+// [lotus] The host's "Mute Screenshare Audio" mutes ONLY screenshare-audio
+// elements, via the same `muted` prop path as deafen (so it survives re-renders
+// and later-published shares); deafen still mutes everything.
+it("screenshareAudioMuted mutes only ScreenShareAudio tracks", () => {
+  const explicitTracks = [
+    {
+      participantId: "@alice:DEV0",
+      kind: Track.Kind.Audio,
+      source: Track.Source.Microphone,
+    },
+    {
+      participantId: "@alice:DEV0",
+      kind: Track.Kind.Audio,
+      source: Track.Source.ScreenShareAudio,
+    },
+  ];
+  const mutedBySource = (r: RenderResult): Record<string, string> =>
+    Object.fromEntries(
+      r
+        .queryAllByTestId("audio")
+        .map((el) => [el.dataset.source, el.dataset.muted]),
+    );
+
+  expect(
+    mutedBySource(
+      renderTestComponent(
+        [{ userId: "@alice", deviceId: "DEV0" }],
+        ["@alice:DEV0"],
+        explicitTracks,
+        { screenshareAudioMuted: true },
+      ),
+    ),
+  ).toEqual({
+    [Track.Source.Microphone]: "false",
+    [Track.Source.ScreenShareAudio]: "true",
+  });
+
+  expect(
+    mutedBySource(
+      renderTestComponent(
+        [{ userId: "@alice", deviceId: "DEV0" }],
+        ["@alice:DEV0"],
+        explicitTracks,
+        { muted: true },
+      ),
+    ),
+  ).toEqual({
+    [Track.Source.Microphone]: "true",
+    [Track.Source.ScreenShareAudio]: "true",
+  });
+});