call: consume self-built Element Call fork + activate Lotus features

Switch to @lotusguild/element-call-embedded@0.20.1-lotus.1 (our self-built
fork) and turn on the source-level features it adds:

- #1 denoise CUTOVER: in-source ML denoise (lotusDenoiseSource=1) replaces
  the build-time getUserMedia shim — removed the shim injection from
  vite.config.js (denoise/ assets still shipped; the processor loads them).
  Survives reconnects (fixes A7).
- #2 call-state: CallEmbed consumes io.lotus.call_state; useCallSpeakers /
  useRemoteAllMuted prefer it over scraping EC's DOM (DOM fallback kept;
  empty payloads ignored).
- #4 focus: CallControl.focusCameraParticipant sends io.lotus.focus_participant
  (works during screenshare), replacing the DOM tile-click hack.
- #5 theming: lotusTransparent=1 (native transparent background).
- #6 decorations: LotusDecorationPusher sends each member's decoration URL
  via io.lotus.decorations -> rendered on in-call tiles.

#3 soundboard / #7 quality ship dormant (EC-ready; no host UI sends them yet).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/features/call/CallView.tsx

@@ -17,6 +17,7 @@ import { useRoomPermissions } from '../../hooks/useRoomPermissions';
 import { useMatrixClient } from '../../hooks/useMatrixClient';
 import { StateEvent } from '../../../types/matrix/room';
 import { useCallMembers, useCallSession } from '../../hooks/useCall';
+import { LotusDecorationPusher } from '../lotus/LotusDecorationPusher';
 import { useStateEvent } from '../../hooks/useStateEvent';
 import { VoiceLimitContent } from '../common-settings/general/RoomVoiceLimit';
 import { CallMemberRenderer } from './CallMemberCard';
@@ -199,6 +200,8 @@ function CallJoined({ joined, containerRef }: CallJoinedProps) {
     <Box grow="Yes" direction="Column">
       <Box grow="Yes" ref={containerRef} />
       {callEmbed && joined && <CallControls callEmbed={callEmbed} />}
+      {/* [lotus #6] push avatar decorations to EC's in-call tiles (post-join) */}
+      {callEmbed && joined && <LotusDecorationPusher callEmbed={callEmbed} />}
     </Box>
   );
 }