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/localMember/LocalTransport.ts

@@ -77,13 +77,12 @@ export const localTransport$ = ({
     scope.behavior(from(makeTransport(client, roomId)), undefined);
 
   /**
-   * The transport we should advertise in our MatrixRTC membership (plus whether
-   * it is a multi-SFU transport and whether we should use sticky events).
+   * The transport we should advertise in our MatrixRTC membership.
    */
   const advertisedTransport$ = scope.behavior(
     combineLatest(
-      [useOldestMember$, preferredTransport$, oldestMemberTransport$],
-      (useOldestMember, preferredTransport, oldestMemberTransport) =>
+      [useOldestMember$, oldestMemberTransport$, preferredTransport$],
+      (useOldestMember, oldestMemberTransport, preferredTransport) =>
         useOldestMember ? oldestMemberTransport : preferredTransport,
     ).pipe<LivekitTransport>(distinctUntilChanged(deepCompare)),
     undefined,