Use the unstable LiveKit transport type

UnstableLivekitTransport covers every shape a homeserver may advertise
while MSC4195 evolves: a LiveKit SFU `url`, a `livekit_service_url`, or
both. Switching to it means a service URL is no longer guaranteed, so the
remaining code that relies on one checks for it explicitly: delegation
probing skips transports without one, the connection map keys transports
by whichever URL they carry, and the OpenID flow rejects transports
without a service URL until the client-server API flow lands.

src/state/SessionBehaviors.ts

@@ -7,10 +7,10 @@ Please see LICENSE in the repository root for full details.
 
 import {
   type CallMembership,
-  type LivekitTransport,
+  type UnstableLivekitTransport,
   type MatrixRTCSession,
   MatrixRTCSessionEvent,
-  isLivekitTransport,
+  isUnstableLivekitTransport,
 } from "matrix-js-sdk/lib/matrixrtc";
 import { fromEvent } from "rxjs";
 
@@ -31,15 +31,17 @@ export const membershipsAndTransports$ = (
   memberships$: Behavior<Epoch<CallMembership[]>>,
 ): {
   membershipsWithTransport$: Behavior<
-    Epoch<{ membership: CallMembership; transport?: LivekitTransport }[]>
+    Epoch<
+      { membership: CallMembership; transport?: UnstableLivekitTransport }[]
+    >
   >;
-  transports$: Behavior<Epoch<LivekitTransport[]>>;
+  transports$: Behavior<Epoch<UnstableLivekitTransport[]>>;
 } => {
   const membershipsWithTransport$: Behavior<
     Epoch<
       {
         membership: CallMembership;
-        transport: LivekitTransport | undefined;
+        transport: UnstableLivekitTransport | undefined;
       }[]
     >
   > = scope.behavior(
@@ -49,18 +51,21 @@ export const membershipsAndTransports$ = (
           const transport = membership.getTransport();
           return {
             membership,
-            transport: isLivekitTransport(transport) ? transport : undefined,
+            transport: isUnstableLivekitTransport(transport)
+              ? transport
+              : undefined,
           };
         });
       }),
     ),
   );
 
-  const transports$: Behavior<Epoch<LivekitTransport[]>> = scope.behavior(
-    membershipsWithTransport$.pipe(
-      mapEpoch((mts) => mts.flatMap(({ transport: t }) => (t ? [t] : []))),
-    ),
-  );
+  const transports$: Behavior<Epoch<UnstableLivekitTransport[]>> =
+    scope.behavior(
+      membershipsWithTransport$.pipe(
+        mapEpoch((mts) => mts.flatMap(({ transport: t }) => (t ? [t] : []))),
+      ),
+    );
 
   return {
     membershipsWithTransport$,