fix(lotus): restart the shared mic sampler only when the LiveKit rooms change (#45)

observeLocalMicSample$ switchMapped on every allConnections$ emission,
which re-emits far more often than the set of rooms changes. Each one
stopped the clone, closed the AudioContext and emitted null, and the
null reset the muted-speech gate, so the "You're muted" nudge could
never stay true long enough to fire. Map to the room list and only
restart when it actually changes.

Fixes #45

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017PCb59uY3UKqDqt7B6hzd5

src/lotus/lotusMicLevel.ts

@@ -46,6 +46,10 @@ const micPublication = (
     : null;
 };
 
+/** Pure: the same LiveKit rooms, in the same order (by identity). */
+export const sameRooms = <T>(a: readonly T[], b: readonly T[]): boolean =>
+  a.length === b.length && a.every((r, i) => r === b[i]);
+
 const samplers = new WeakMap<
   CallViewModel,
   Observable<LocalMicSample | null>
@@ -62,10 +66,15 @@ export function observeLocalMicSample$(
   const cached = samplers.get(vm);
   if (cached) return cached;
   const sampler$ = vm.allConnections$.pipe(
+    map((data) => data.getConnections().map((c) => c.livekitRoom)),
+    // [EC #45] allConnections$ re-emits far more often than the set of
+    // LiveKit rooms changes; restarting the tap each time closed the
+    // AudioContext ~1×/s and emitted null, which reset the muted-speech
+    // gate so the "You're muted" nudge could never fire.
+    distinctUntilChanged(sameRooms),
     switchMap(
-      (data) =>
+      (rooms) =>
         new Observable<LocalMicSample | null>((subscriber) => {
-          const rooms = data.getConnections().map((c) => c.livekitRoom);
           let ctx: AudioContext | null = null;
           let clone: MediaStreamTrack | null = null;
           let timer: ReturnType<typeof setInterval> | undefined;