feat: add screen share audio support

Pass audio: true to setScreenShareEnabled so the browser offers the
"Share audio" checkbox. Track ScreenShareAudio from remote participants
and play it through a dedicated audio element with the same volume
pipeline (including boost >100%).

packages/web/src/components/voice/DmCallView.tsx

@@ -89,12 +89,19 @@ export function DmCallView() {
     toggleCamera();
   };
 
-  const handleScreenShare = () => {
+  const handleScreenShare = async () => {
     const room = getActiveRoom();
-    if (room) {
-      room.localParticipant.setScreenShareEnabled(!isScreenSharing);
+    if (!room) return;
+    try {
+      if (!isScreenSharing) {
+        await room.localParticipant.setScreenShareEnabled(true, { audio: true });
+      } else {
+        await room.localParticipant.setScreenShareEnabled(false);
+      }
+      toggleScreenShare();
+    } catch (err) {
+      console.error('[DmCallView] Failed to toggle screen share:', err);
     }
-    toggleScreenShare();
   };
 
   const handleEndCall = () => {