fix(lotus): implement deafen via EC's global output mute, not setVolume

Deafen wrote RemoteParticipant.setVolume(0, Microphone), which EC's own
createVolumeControls overwrote with the tile volume every time sink$
re-emitted (every join / re-resolution) — so anyone joining while you were
deafened was audible — and undeafen blanket-wrote 1 to every participant,
clobbering per-tile volume/mute. The ParticipantConnected listeners also
hung off livekitRoomItems$, which is empty while alone, so the first joiner
could be heard briefly.

Deafen now drives setAudioEnabled$ -> muteAllAudio$, the `muted` prop
InCallView already passes to every audio renderer, which also silences
Track.Source.Unknown soundboard audio (the known P6-2 gap). Undeafen
restores the user's own output state and never touches the mute-all
setting. Re-applying the same state is a no-op so resendForkState() is
safe. Screenshare-audio-only mute keeps setVolume(ScreenShareAudio) but
only restores participants it muted itself. Rooms come from
allConnections$ like the sibling modules. Unit-tested.

Fixes #1

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

src/lotus/lotusDeafen.test.ts

@@ -0,0 +1,154 @@
+/*
+Copyright 2026 Lotus Guild
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { EventEmitter } from "events";
+import { afterEach, beforeEach, expect, test, vi } from "vitest";
+import { of } from "rxjs";
+import { Track } from "livekit-client";
+
+import { type CallViewModel } from "../state/CallViewModel/CallViewModel";
+import { setAudioEnabled$ } from "../controls";
+import { startLotusDeafen } from "./lotusDeafen";
+import { LotusWidgetActions } from "./lotusActions";
+
+const lazyActions = new EventEmitter();
+
+vi.mock("../widget", () => ({
+  widget: {
+    api: { transport: { reply: vi.fn().mockResolvedValue(undefined) } },
+    // Getter: `vi.mock` factories run at import time, before the const above.
+    get lazyActions(): EventEmitter {
+      return lazyActions;
+    },
+  },
+}));
+
+/** Minimal CallViewModel stub: no connections, so no livekit rooms. */
+function mockVm(participants: unknown[] = []): CallViewModel {
+  const livekitRoom = {
+    remoteParticipants: new Map(participants.map((p, i) => [String(i), p])),
+    on: vi.fn(),
+    off: vi.fn(),
+  };
+  return {
+    allConnections$: of({ getConnections: () => [{ livekitRoom }] }),
+  } as unknown as CallViewModel;
+}
+
+function send(data: unknown): void {
+  lazyActions.emit(LotusWidgetActions.SetDeafen, {
+    detail: { data },
+  });
+}
+
+/** Records everything pushed to the global audio-output subject. */
+let emissions: boolean[];
+let sub: { unsubscribe: () => void };
+
+beforeEach(() => {
+  emissions = [];
+  sub = setAudioEnabled$.subscribe((v) => emissions.push(v));
+});
+
+afterEach(() => {
+  sub.unsubscribe();
+  lazyActions.removeAllListeners();
+});
+
+test("deafen mutes, and undeafen unmutes, EC's global audio output", () => {
+  const stop = startLotusDeafen(mockVm());
+
+  send({ deafened: true, screenshareAudioMuted: false });
+  expect(emissions).toEqual([false]);
+
+  send({ deafened: false, screenshareAudioMuted: false });
+  expect(emissions).toEqual([false, true]);
+
+  stop();
+  expect(emissions).toEqual([false, true]);
+});
+
+test("re-sending the same state is idempotent (host resendForkState)", () => {
+  const stop = startLotusDeafen(mockVm());
+
+  send({ deafened: true, screenshareAudioMuted: false });
+  send({ deafened: true, screenshareAudioMuted: false });
+  send({ deafened: true, screenshareAudioMuted: false });
+  expect(emissions).toEqual([false]);
+
+  stop();
+  // Teardown restores the user's own state, which was "audio enabled".
+  expect(emissions).toEqual([false, true]);
+});
+
+test("undeafen does not re-enable audio the user had muted themselves", () => {
+  const stop = startLotusDeafen(mockVm());
+
+  // The user mutes all audio through EC's own control first.
+  setAudioEnabled$.next(false);
+  expect(emissions).toEqual([false]);
+
+  send({ deafened: true, screenshareAudioMuted: false });
+  send({ deafened: false, screenshareAudioMuted: false });
+  // Nothing further was pushed: audio was already off and stays off.
+  expect(emissions).toEqual([false]);
+
+  stop();
+  expect(emissions).toEqual([false]);
+});
+
+test("deafen never touches per-participant volume", () => {
+  const participant = { setVolume: vi.fn() };
+  const stop = startLotusDeafen(mockVm([participant]));
+
+  send({ deafened: true, screenshareAudioMuted: false });
+  send({ deafened: false, screenshareAudioMuted: false });
+  expect(participant.setVolume).not.toHaveBeenCalled();
+
+  stop();
+});
+
+test("screenshare-audio mute is applied per source and only undone for participants we muted", () => {
+  const participant = { setVolume: vi.fn() };
+  const stop = startLotusDeafen(mockVm([participant]));
+
+  // Not muted yet: no volume writes at all.
+  send({ deafened: false, screenshareAudioMuted: false });
+  expect(participant.setVolume).not.toHaveBeenCalled();
+
+  send({ deafened: false, screenshareAudioMuted: true });
+  expect(participant.setVolume).toHaveBeenCalledWith(
+    0,
+    Track.Source.ScreenShareAudio,
+  );
+
+  participant.setVolume.mockClear();
+  send({ deafened: false, screenshareAudioMuted: false });
+  expect(participant.setVolume).toHaveBeenCalledWith(
+    1,
+    Track.Source.ScreenShareAudio,
+  );
+
+  // Releasing again writes nothing: we no longer own that participant.
+  participant.setVolume.mockClear();
+  send({ deafened: false, screenshareAudioMuted: false });
+  expect(participant.setVolume).not.toHaveBeenCalled();
+
+  stop();
+});
+
+test("a partial payload only moves the flag it names", () => {
+  const stop = startLotusDeafen(mockVm());
+
+  send({ deafened: true });
+  expect(emissions).toEqual([false]);
+  send({ screenshareAudioMuted: true });
+  // Still deafened: no change to the global mute.
+  expect(emissions).toEqual([false]);
+
+  stop();
+});