lotus(#2): stream per-participant call state over widget API

Opt-in (lotusCallState=1) bridge that emits io.lotus.call_state with each
participant's speaking/audio/video state, so the Lotus host can drive
speaking rings / mute badges / PiP from real events instead of scraping
EC's rendered DOM. Exposes vm.userMedia$ on the public CallViewModel.
Additive: no-op without the flag.

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

src/room/InCallView.tsx

@@ -29,6 +29,7 @@ import { Header, LeftNav, RightNav, RoomHeaderInfo } from "../Header";
 import { HeaderStyle, useUrlParams } from "../UrlParams";
 import { useCallViewKeyboardShortcuts } from "../useCallViewKeyboardShortcuts";
 import { widget } from "../widget";
+import { startLotusCallState } from "../lotus/lotusCallState";
 import styles from "./InCallView.module.css";
 import { GridTile } from "../tile/GridTile";
 import { SettingsModal, defaultSettingsTab } from "../settings/SettingsModal";
@@ -279,6 +280,10 @@ export const InCallView: FC<InCallViewProps> = ({
   const earpieceMode = useBehavior(vm.earpieceMode$);
   const audioOutputSwitcher = useBehavior(vm.audioOutputSwitcher$);
 
+  // [lotus] Stream per-participant speaking/mute state to the host (cinny) over
+  // the widget API when opted in via lotusCallState=1. No-op otherwise.
+  useEffect(() => startLotusCallState(vm), [vm]);
+
   const fatalCallError = useBehavior(vm.fatalError$);
   // Stop the rendering and throw for the error boundary
   if (fatalCallError) {