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.tsx

@@ -38,6 +38,12 @@ export interface MatrixAudioRendererProps {
    * If set to `true`, the server will stop sending audio track data to the client.
    */
   muted?: boolean;
+  /**
+   * [lotus] If set to `true`, mutes only the `Track.Source.ScreenShareAudio`
+   * tracks (the host's "Mute Screenshare Audio" control) — same mechanism as
+   * `muted`, so it holds across re-renders and later-published shares.
+   */
+  screenshareAudioMuted?: boolean;
 }
 
 /**
@@ -58,6 +64,7 @@ export function LivekitRoomAudioRenderer({
   livekitRoom,
   validIdentities,
   muted,
+  screenshareAudioMuted,
 }: MatrixAudioRendererProps): ReactNode {
   const logger = rootLogger.getChild("[MatrixAudioRenderer]");
   const tracks = useTracks(
@@ -143,7 +150,11 @@ export function LivekitRoomAudioRenderer({
         <AudioTrackWithAudioNodes
           key={getTrackReferenceId(trackRef)}
           trackRef={trackRef}
-          muted={muted}
+          muted={
+            muted ||
+            (screenshareAudioMuted &&
+              trackRef.publication.source === Track.Source.ScreenShareAudio)
+          }
           audioContext={shouldUseAudioContext ? audioContext : undefined}
           audioNodes={audioNodes}
         />