Refactor Matrix/LiveKit session merging

- Replace MatrixLivekitItem with MatrixLivekitMember, add displayName$
  and participantId, and use explicit LiveKit participant types
- Make sessionBehaviors$ accept a props object and return a typed
  RxRtcSession
- Update CallViewModel to use the new session behaviors, rebuild media
  items from matrixLivekitMembers, handle missing connections and use
  participantId-based keys
- Change localMembership/localTransport to accept Behavior-based
  options, read options.value for enterRTCSession, and fix advertised
  transport selection order
- Update tests and minor UI adjustments (settings modal livekitRooms
  stubbed) and fix JSON formatting in locales

src/state/remoteMembers/ConnectionManager.ts

@@ -107,7 +107,7 @@ export class ConnectionManager {
     private readonly connectionFactory: ConnectionFactory,
     private readonly inputTransports$: Behavior<LivekitTransport[]>,
   ) {
-    // TODO logger: only construct one logger from the client and make it compatible via a EC specific singleton.
+    // TODO logger: only construct one logger from the client and make it compatible via a EC specific sing
     this.logger = logger.getChild("ConnectionManager");
     scope.onEnd(() => this.running$.next(false));
   }