fix(engine): delay session close teardown 2s

internal/engine/goolom/lifecycle.go

@@ -197,8 +197,13 @@ func (s *Session) Close() error {
 	if !alreadyClosing {
 		leaveUID := uuid.New().String()
 		leaveAck := s.registerAckWaiter(leaveUID)
+		// 2s matches our jitsi tear-down budget. The reason is the same:
+		// without giving the server time to register the leave, a
+		// back-to-back reconnection from the same client collides with a
+		// still-alive ghost participant on the SFU side and inherits
+		// stale media-flow state.
 		if s.sendLeave(leaveUID) {
-			_ = s.waitForAck(leaveUID, leaveAck, 1500*time.Millisecond)
+			_ = s.waitForAck(leaveUID, leaveAck, 2*time.Second)
 		} else {
 			s.removeAckWaiter(leaveUID)
 		}

internal/engine/livekit/livekit.go

@@ -188,6 +188,14 @@ func (s *Session) Close() error {
 		if s.room != nil {
 			s.unpublishLocalTracks()
 			s.room.Disconnect()
+			// LiveKit's Disconnect() returns once the local SDK state
+			// is torn down, not when the server has actually evicted
+			// the participant. Without giving the signalling channel
+			// time to flush the LEAVE_REQUEST and the server to act on
+			// it, a back-to-back reconnect from the same identity in
+			// the same room sees a still-alive ghost participant on
+			// the SFU and inherits stale publication state.
+			time.Sleep(2 * time.Second)
 		}
 		close(s.sendQueue)
 		s.wg.Wait()