fix(lotus): report an ended screenshare even when LiveKit unpublishes first (#39)

LiveKit's own ended handler runs before ours and unpublishes the share;
a listener removed during that dispatch never fires. Decide from the
track's readyState on LocalTrackUnpublished as well. Verified end to end:
closing the shared source now toasts in the host.

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

src/lotus/lotusScreenshareWatch.test.ts

@@ -132,6 +132,23 @@ describe("startLotusScreenshareWatch", () => {
     stop();
   });
 
+  it("reports ended from the unpublish when LiveKit's handler ran first", () => {
+    const { emit, stop } = start();
+    const share = new FakeTrack() as FakeTrack & { readyState: string };
+    share.readyState = "ended";
+    const pub = {
+      source: Track.Source.ScreenShare,
+      track: { mediaStreamTrack: share },
+    };
+    emit(RoomEvent.LocalTrackPublished, pub);
+    emit(RoomEvent.LocalTrackUnpublished, pub);
+    share.dispatchEvent(new Event("ended"));
+    expect(sent).toEqual([
+      { action: "io.lotus.screenshare_notice", data: { kind: "ended" } },
+    ]);
+    stop();
+  });
+
   it("ignores non-screenshare publications and stops watching on unpublish", () => {
     const { emit, stop } = start();
     const cam = new FakeTrack();