feat(calls): audio output quick-switch in the call bar (#119)

Verified first: the embed hides Element Call's footer, so its in-call
settings sheet (which has the output picker) is unreachable from Lotus;
the cinny call bar had no output control.

Now a speaker button next to Deafen (desktop bar only; hidden where
setSinkId is unavailable — Firefox, Safari, Android Chrome) opens a menu
of enumerateDevices() audio outputs with the current one checked; picking
one sends io.lotus.set_audio_output to the fork (≥ 0.25.0-lotus.11),
which selects it, and the choice is re-sent with the rest of the sticky
fork state after an EC remount.

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

src/app/features/call-status/CallControl.tsx

@@ -8,6 +8,7 @@ import { callEmbedAtom } from '../../state/callEmbed';
 import { MobileTouchTarget } from '../../styles/mobile.css';
 import { useRoomCallPolicy } from '../../hooks/useRoomCallPolicy';
 import { ScreenshareConfirm } from '../call/ScreenshareConfirm';
+import { AudioOutputButton, audioOutputSelectable } from './AudioOutputButton';
 
 type MicrophoneButtonProps = {
   enabled: boolean;
@@ -230,6 +231,9 @@ export function CallControl({
           onToggle={() => callEmbed.control.toggleSound()}
           disabled={!callJoined}
         />
+        {!compact && audioOutputSelectable() && (
+          <AudioOutputButton embed={callEmbed} disabled={!callJoined} />
+        )}
         {!compact && (showCamera || showScreenshare) && <StatusDivider />}
         {showCamera && (
           <VideoButton enabled={video} onToggle={handleVideoToggle} disabled={!callJoined} />