fix: Fix users unable to see or hear each other in voice channels due to

stale server sockets, passive non-initiators, and race conditions
during peer connection setup.

Fix users unable to see or hear each other in voice channels due to
stale server sockets, passive non-initiators, and race conditions
during peer connection setup.

Server:
- Close stale WebSocket connections sharing the same oderId in
  handleIdentify instead of letting them linger up to 45s
- Make user_joined/user_left broadcasts identity-aware so duplicate
  sockets don't produce phantom join/leave events
- Include serverIds in user_left payload for multi-room presence
- Simplify findUserByOderId now that stale sockets are cleaned up

Client - signaling:
- Add fallback offer system with 1s timer for missed user_joined races
- Add non-initiator takeover after 5s when the initiator fails to send
  an offer (NON_INITIATOR_GIVE_UP_MS)
- Scope peerServerMap per signaling URL to prevent cross-server
  collisions
- Add socket identity guards on all signaling event handlers
- Replace canReusePeerConnection with hasActivePeerConnection and
  isPeerConnectionNegotiating with extended grace periods

Client - peer connections:
- Extract replaceUnusablePeer helper to deduplicate stale peer
  replacement in offer and ICE handlers
- Add stale connectionstatechange guard to ignore events from replaced
  RTCPeerConnection instances
- Use deterministic initiator election in peer recovery reconnects
- Track createdAt on PeerData for staleness detection

Client - presence:
- Add multi-room presence tracking via presenceServerIds on User
- Replace clearUsers + individual userJoined with syncServerPresence
  for atomic server roster updates
- Make userLeft handle partial server removal instead of full eviction

Documentation:
- Add server-side connection hygiene, non-initiator takeover, and stale
  peer replacement sections to the realtime README

toju-app/src/app/features/room/rooms-side-panel/rooms-side-panel.component.ts

@@ -125,8 +125,13 @@ export class RoomsSidePanelComponent {
   });
   onlineRoomUsers = computed(() => {
     const memberIdentifiers = this.roomMemberIdentifiers();
+    const roomId = this.currentRoom()?.id;
 
-    return this.onlineUsers().filter((user) => !this.isCurrentUserIdentity(user) && this.matchesIdentifiers(memberIdentifiers, user));
+    return this.onlineUsers().filter((user) =>
+      !this.isCurrentUserIdentity(user)
+      && this.matchesIdentifiers(memberIdentifiers, user)
+      && this.isUserPresentInRoom(user, roomId)
+    );
   });
   offlineRoomMembers = computed(() => {
     const onlineIdentifiers = new Set<string>();
@@ -200,6 +205,14 @@ export class RoomsSidePanelComponent {
     return !!((entity.id && identifiers.has(entity.id)) || (entity.oderId && identifiers.has(entity.oderId)));
   }
 
+  private isUserPresentInRoom(entity: { presenceServerIds?: string[] }, roomId: string | undefined): boolean {
+    if (!roomId || !Array.isArray(entity.presenceServerIds) || entity.presenceServerIds.length === 0) {
+      return true;
+    }
+
+    return entity.presenceServerIds.includes(roomId);
+  }
+
   private isCurrentUserIdentity(entity: { id?: string; oderId?: string }): boolean {
     const current = this.currentUser();