✨(frontend) let authenticated users manage the lobby on trusted rooms

Frontend counterpart of the trusted-lobby backend feature: on
`trusted` rooms, any authenticated participant sees the waiting
notification and can accept or deny entry requests, not only admins
and owners.

Gating moves from role to capability: `useCanManageLobby` mirrors
the backend permission and derives from `useRoomData()`. Room
metadata is already synced into the query cache, so an access-level
change mid-meeting recomputes the capability on every client with no
new sync mechanism. It is only a UI gate; the backend re-checks
everything per request and fails closed.

Fetching moves into a single room-level `LobbyProvider`: the hook
was previously instantiated by two components and only worked
because React Query deduplicated their queries. The provider owns
one query and an explicit state machine - ways in (connection
established, ParticipantWaiting broadcast, panel opened, rights
regained while the panel is open) all arm and fetch; ways out
(rights lost, server 401/403) disarm and clear the cached list so
nothing stale can render.

Polling is tiered by audience since managers grow from a few admins
to potentially the whole room: 1s when acting (panel open),
10s when the notification is shown, and zero when the list is empty -
decided in the refetchInterval callback because structural sharing
suppresses data-keyed effects on identical empty responses. A quiet
room costs nothing; fetches are triggered by uncorrelated human
events, never synchronized across the room (the rights-regained
trigger is panel-gated for this reason).

src/frontend/src/features/participants/hooks/useWaitingParticipants.ts

@@ -1,61 +1,31 @@
-import { useCallback, useEffect, useMemo, useState } from 'react'
-import { useRoomContext } from '@livekit/components-react'
-import { RoomEvent } from 'livekit-client'
+import { useMemo } from 'react'
+
 import { useRoomData } from '@/features/rooms/livekit/hooks/useRoomData'
-import { useIsAdminOrOwner } from '@/features/rooms/livekit/hooks/useIsAdminOrOwner'
+import { useCanManageLobby } from '@/features/rooms/livekit/hooks/useCanManageLobby'
 import { useEnterRoom } from '../api/enterRoom'
 import {
   useListWaitingParticipants,
   type WaitingParticipant,
 } from '../../participants/api/listWaitingParticipants'
-import { decodeNotificationDataReceived } from '@/features/notifications/utils'
-import { NotificationType } from '@/features/notifications/NotificationType'
 import { reportError } from '@/features/analytics/telemetry'
 
-export const POLL_INTERVAL_MS = 1000
-
 export const useWaitingParticipants = () => {
-  const [listEnabled, setListEnabled] = useState(true)
-
   const roomData = useRoomData()
   const roomId = roomData?.id || '' // FIXME - bad practice
 
-  const room = useRoomContext()
-  const isAdminOrOwner = useIsAdminOrOwner()
-
-  const handleDataReceived = useCallback((payload: Uint8Array) => {
-    const notification = decodeNotificationDataReceived(payload)
-    if (notification?.type === NotificationType.ParticipantWaiting) {
-      setListEnabled(true)
-    }
-  }, [])
-
-  useEffect(() => {
-    if (isAdminOrOwner) {
-      room.on(RoomEvent.DataReceived, handleDataReceived)
-    }
-    return () => {
-      room.off(RoomEvent.DataReceived, handleDataReceived)
-    }
-  }, [isAdminOrOwner, room, handleDataReceived])
+  const canManageLobby = useCanManageLobby()
 
   const { data: waitingData, refetch: refetchWaiting } =
     useListWaitingParticipants(roomId, {
       retry: false,
-      enabled: listEnabled && isAdminOrOwner,
-      refetchInterval: POLL_INTERVAL_MS,
-      refetchIntervalInBackground: true,
+      enabled: false,
     })
 
   const waitingParticipants = useMemo(
-    () => waitingData?.participants || [],
-    [waitingData]
+    () => (canManageLobby ? waitingData?.participants || [] : []),
+    [waitingData, canManageLobby]
   )
 
-  useEffect(() => {
-    if (!waitingParticipants.length) setListEnabled(false)
-  }, [waitingParticipants])
-
   const { mutateAsync: enterRoom } = useEnterRoom()
 
   const handleParticipantEntry = async (
@@ -74,8 +44,6 @@ export const useWaitingParticipants = () => {
     allowEntry: boolean
   ): Promise<void> => {
     try {
-      setListEnabled(false)
-
       await Promise.all(
         waitingParticipants.map((participant) =>
           enterRoom({
@@ -89,7 +57,6 @@ export const useWaitingParticipants = () => {
       await refetchWaiting()
     } catch (e) {
       reportError('generic_failure', e)
-      setListEnabled(true)
     }
   }
 

src/frontend/src/features/rooms/components/LobbyProvider.tsx

@@ -0,0 +1,114 @@
+import { useCallback, useEffect } from 'react'
+import { useConnectionState, useRoomContext } from '@livekit/components-react'
+import { ConnectionState, RoomEvent } from 'livekit-client'
+import { useCanManageLobby } from '@/features/rooms/livekit/hooks/useCanManageLobby'
+import { useRoomData } from '@/features/rooms/livekit/hooks/useRoomData'
+import { useListWaitingParticipants } from '@/features/participants/api/listWaitingParticipants'
+import { useSidePanel } from '@/features/rooms/livekit/hooks/useSidePanel'
+import { decodeNotificationDataReceived } from '@/features/notifications/utils'
+import { NotificationType } from '@/features/notifications'
+import { usePrevious } from '@/hooks/usePrevious'
+import { keys } from '@/api/queryKeys'
+import { queryClient } from '@/api/queryClient'
+import { ApiError } from '@/api/ApiError'
+
+export const POLL_INTERVAL_MS = 1000
+export const LAZY_POLL_INTERVAL_MS = 10_000
+
+export const LobbyProvider = () => {
+  const room = useRoomContext()
+
+  const canManageLobby = useCanManageLobby()
+  const roomData = useRoomData()
+  const { isParticipantsOpen } = useSidePanel()
+  const isConnected = useConnectionState(room) === ConnectionState.Connected
+
+  const roomId = roomData?.id || '' // FIXME - bad practice
+
+  const { error: waitingError, refetch: refetchWaiting } =
+    useListWaitingParticipants(roomId, {
+      retry: false,
+      enabled: canManageLobby && isConnected && !!roomId,
+      refetchOnMount: false,
+      refetchOnWindowFocus: false,
+      refetchOnReconnect: false,
+      refetchInterval: (query) => {
+        if (!query.state.data?.participants?.length) return false
+        if (isParticipantsOpen) return POLL_INTERVAL_MS
+        return LAZY_POLL_INTERVAL_MS
+      },
+      refetchIntervalInBackground: true,
+    })
+
+  // Triggers: each one-shot, idempotent, deduped by React Query if
+  // concurrent. The interval takes over whenever a fetch finds waiters.
+  const fetchIfManager = useCallback(() => {
+    if (canManageLobby) refetchWaiting()
+  }, [canManageLobby, refetchWaiting])
+
+  // 1. Connection established (join or reconnect)
+  useEffect(() => {
+    room.on(RoomEvent.Connected, fetchIfManager)
+    room.on(RoomEvent.Reconnected, fetchIfManager)
+    return () => {
+      room.off(RoomEvent.Connected, fetchIfManager)
+      room.off(RoomEvent.Reconnected, fetchIfManager)
+    }
+  }, [room, fetchIfManager])
+
+  // 2. Someone started waiting (LiveKit broadcast).
+  const handleDataReceived = useCallback(
+    (payload: Uint8Array) => {
+      const notification = decodeNotificationDataReceived(payload)
+      if (notification?.type === NotificationType.ParticipantWaiting) {
+        fetchIfManager()
+      }
+    },
+    [fetchIfManager]
+  )
+
+  useEffect(() => {
+    if (canManageLobby) {
+      room.on(RoomEvent.DataReceived, handleDataReceived)
+    }
+    return () => {
+      room.off(RoomEvent.DataReceived, handleDataReceived)
+    }
+  }, [canManageLobby, room, handleDataReceived])
+
+  // 3. Rights regained.
+  const prevCanManageLobby = usePrevious(canManageLobby)
+  useEffect(() => {
+    if (!prevCanManageLobby && canManageLobby && isConnected) {
+      fetchIfManager()
+    }
+  }, [
+    prevCanManageLobby,
+    canManageLobby,
+    isParticipantsOpen,
+    fetchIfManager,
+    isConnected,
+  ])
+
+  const clearWaitingList = useCallback(() => {
+    const queryKey = [keys.waitingParticipants, roomId]
+    queryClient.cancelQueries({ queryKey })
+    queryClient.setQueryData(queryKey, { participants: [] })
+  }, [roomId])
+
+  // Rights lost mid-meeting (covers trusted -> restricted/public).
+  useEffect(() => {
+    if (prevCanManageLobby && !canManageLobby) clearWaitingList()
+  }, [prevCanManageLobby, canManageLobby, clearWaitingList])
+
+  useEffect(() => {
+    if (
+      waitingError instanceof ApiError &&
+      [401, 403].includes(waitingError.statusCode)
+    ) {
+      clearWaitingList()
+    }
+  }, [waitingError, clearWaitingList])
+
+  return null
+}

src/frontend/src/features/rooms/livekit/hooks/useCanManageLobby.ts

@@ -0,0 +1,17 @@
+import { useUser } from '@/features/auth/api/useUser'
+import { ApiAccessLevel } from '@/features/rooms/api/ApiRoom'
+import { useIsAdminOrOwner } from './useIsAdminOrOwner'
+import { useRoomData } from './useRoomData'
+
+export const useCanManageLobby = () => {
+  const isAdminOrOwner = useIsAdminOrOwner()
+  const { isLoggedIn } = useUser()
+  const roomData = useRoomData()
+
+  return (
+    (isAdminOrOwner ||
+      (isLoggedIn === true &&
+        roomData?.access_level === ApiAccessLevel.TRUSTED)) &&
+    roomData?.access_level !== ApiAccessLevel.PUBLIC
+  )
+}

src/frontend/src/features/rooms/livekit/prefabs/VideoConference.tsx

@@ -31,6 +31,7 @@ import { PinAnnouncer } from '@/features/layout/components/PinAnnouncer'
 import { ChatProvider } from '@/features/chat/components/ChatProvider'
 import { SyncDevicePreferences } from '@/features/rooms/livekit/components/SyncDevicePreferences'
 import { RoomSilentMicDetector } from '@/features/rooms/components/SilentMicDetector'
+import { LobbyProvider } from '@/features/rooms/components/LobbyProvider'
 
 /**
  * @public
@@ -120,6 +121,7 @@ export function VideoConference({ ...props }: VideoConferenceProps) {
       <RoomSilentMicDetector />
       <MediaStateObserver />
       <ChatProvider />
+      <LobbyProvider />
       <VideoResolutionSubscription />
       <div
         className="lk-video-conference"