feat: display room info and network players in mini app nav

When users are in a room (/arcade/rooms/[roomId]/*), the mini app nav now shows:
1. Room name and game type in RoomInfo component
2. Other members' player avatars with "network" indicators
3. Clear distinction between local players and network players

Implementation:
- Created useRoomData hook to fetch room data and listen to real-time updates
- Updated PageWithNav to use room data and compute network players
- Enhanced RoomInfo component to display room name when available
- Network players shown with special borders and connection indicators

The nav automatically detects room context from the URL and fetches:
- Room details (name, game, member count)
- All room members and their players
- Real-time updates via socket events (member-joined, member-left, players-updated)

Network players are filtered to exclude the current user and show each other
member's players with their display names for clear identification.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

apps/web/src/components/PageWithNav.tsx

@@ -3,6 +3,8 @@
 import React from 'react'
 import { useGameMode } from '../contexts/GameModeContext'
 import { useArcadeGuard } from '../hooks/useArcadeGuard'
+import { useRoomData } from '../hooks/useRoomData'
+import { useViewerId } from '../hooks/useViewerId'
 import { AppNavBar } from './AppNavBar'
 import { GameContextNav } from './nav/GameContextNav'
 import { PlayerConfigDialog } from './nav/PlayerConfigDialog'
@@ -30,6 +32,8 @@ export function PageWithNav({
 }: PageWithNavProps) {
   const { players, activePlayers, setActive, activePlayerCount } = useGameMode()
   const { hasActiveSession, activeSession } = useArcadeGuard({ enabled: false }) // Don't redirect, just get info
+  const { roomData, isInRoom } = useRoomData()
+  const { data: viewerId } = useViewerId()
   const [mounted, setMounted] = React.useState(false)
   const [configurePlayerId, setConfigurePlayerId] = React.useState<string | null>(null)
 
@@ -80,17 +84,33 @@ export function PageWithNav({
 
   // Compute arcade session info for display
   const roomInfo =
-    hasActiveSession && activeSession
+    isInRoom && roomData
       ? {
-          gameName: activeSession.currentGame,
-          playerCount: activePlayerCount, // TODO: Get actual player count from session when available
+          roomName: roomData.name,
+          gameName: roomData.gameName,
+          playerCount: roomData.members.length,
         }
-      : undefined
+      : hasActiveSession && activeSession
+        ? {
+            gameName: activeSession.currentGame,
+            playerCount: activePlayerCount,
+          }
+        : undefined
 
-  // Compute network players (other players in the arcade session)
-  // For now, we don't have this info in activeSession, so return empty array
-  // TODO: When arcade room system is implemented, fetch other players from session
-  const networkPlayers: Array<{ id: string; emoji?: string; name?: string }> = []
+  // Compute network players (other players in the room, excluding current user)
+  const networkPlayers: Array<{ id: string; emoji?: string; name?: string }> =
+    isInRoom && roomData
+      ? roomData.members
+          .filter((member) => member.userId !== viewerId)
+          .flatMap((member) => {
+            const memberPlayerList = roomData.memberPlayers[member.userId] || []
+            return memberPlayerList.map((player) => ({
+              id: player.id,
+              emoji: player.emoji,
+              name: `${player.name} (${member.displayName})`,
+            }))
+          })
+      : []
 
   // Create nav content if title is provided
   const navContent = navTitle ? (

apps/web/src/components/nav/GameContextNav.tsx

@@ -22,6 +22,7 @@ interface NetworkPlayer {
 }
 
 interface ArcadeRoomInfo {
+  roomName?: string
   gameName: string
   playerCount: number
 }
@@ -134,6 +135,7 @@ export function GameContextNav({
         {/* Room Info - show when in arcade session */}
         {roomInfo && !showFullscreenSelection && (
           <RoomInfo
+            roomName={roomInfo.roomName}
             gameName={roomInfo.gameName}
             playerCount={roomInfo.playerCount}
             shouldEmphasize={shouldEmphasize}

apps/web/src/components/nav/RoomInfo.tsx

@@ -1,4 +1,5 @@
 interface RoomInfoProps {
+  roomName?: string
   gameName: string
   playerCount: number
   shouldEmphasize: boolean
@@ -7,7 +8,7 @@ interface RoomInfoProps {
 /**
  * Displays current arcade room/session information
  */
-export function RoomInfo({ gameName, playerCount, shouldEmphasize }: RoomInfoProps) {
+export function RoomInfo({ roomName, gameName, playerCount, shouldEmphasize }: RoomInfoProps) {
   return (
     <div
       style={{
@@ -53,7 +54,7 @@ export function RoomInfo({ gameName, playerCount, shouldEmphasize }: RoomInfoPro
             letterSpacing: '0.5px',
           }}
         >
-          Arcade Session
+          {roomName ? 'Room' : 'Arcade Session'}
         </div>
         <div
           style={{
@@ -61,7 +62,7 @@ export function RoomInfo({ gameName, playerCount, shouldEmphasize }: RoomInfoPro
             fontWeight: 'bold',
           }}
         >
-          {gameName}
+          {roomName || gameName}
         </div>
       </div>
 

apps/web/src/hooks/useRoomData.ts

@@ -0,0 +1,162 @@
+import { useEffect, useState } from 'react'
+import { usePathname } from 'next/navigation'
+import { io, type Socket } from 'socket.io-client'
+
+export interface RoomMember {
+  id: string
+  userId: string
+  displayName: string
+  isOnline: boolean
+  isCreator: boolean
+}
+
+export interface RoomPlayer {
+  id: string
+  name: string
+  emoji: string
+  color: string
+}
+
+export interface RoomData {
+  id: string
+  name: string
+  code: string
+  gameName: string
+  members: RoomMember[]
+  memberPlayers: Record<string, RoomPlayer[]> // userId -> players
+}
+
+/**
+ * Hook to fetch and subscribe to room data when on a room page
+ * Returns null if not on a room page
+ */
+export function useRoomData() {
+  const pathname = usePathname()
+  const [socket, setSocket] = useState<Socket | null>(null)
+  const [roomData, setRoomData] = useState<RoomData | null>(null)
+  const [isLoading, setIsLoading] = useState(false)
+
+  // Extract roomId from pathname like /arcade/rooms/[roomId]/...
+  const roomId = pathname?.match(/\/arcade\/rooms\/([^/]+)/)?.[1]
+
+  // Initialize socket connection when on a room page
+  useEffect(() => {
+    if (!roomId) {
+      if (socket) {
+        socket.disconnect()
+        setSocket(null)
+      }
+      return
+    }
+
+    const sock = io({ path: '/api/socket' })
+    setSocket(sock)
+
+    return () => {
+      sock.disconnect()
+    }
+  }, [roomId])
+
+  useEffect(() => {
+    if (!roomId) {
+      setRoomData(null)
+      return
+    }
+
+    setIsLoading(true)
+
+    // Fetch initial room data
+    fetch(`/api/arcade/rooms/${roomId}`)
+      .then((res) => {
+        if (!res.ok) throw new Error('Failed to fetch room')
+        return res.json()
+      })
+      .then((data) => {
+        setRoomData({
+          id: data.room.id,
+          name: data.room.name,
+          code: data.room.code,
+          gameName: data.room.gameName,
+          members: data.members || [],
+          memberPlayers: data.memberPlayers || {},
+        })
+        setIsLoading(false)
+      })
+      .catch((error) => {
+        console.error('Failed to fetch room data:', error)
+        setIsLoading(false)
+      })
+  }, [roomId])
+
+  // Subscribe to real-time updates via socket
+  useEffect(() => {
+    if (!socket || !roomId) return
+
+    const handleMemberJoined = (data: {
+      roomId: string
+      userId: string
+      members: RoomMember[]
+      memberPlayers: Record<string, RoomPlayer[]>
+    }) => {
+      if (data.roomId === roomId) {
+        setRoomData((prev) => {
+          if (!prev) return null
+          return {
+            ...prev,
+            members: data.members,
+            memberPlayers: data.memberPlayers,
+          }
+        })
+      }
+    }
+
+    const handleMemberLeft = (data: {
+      roomId: string
+      userId: string
+      members: RoomMember[]
+      memberPlayers: Record<string, RoomPlayer[]>
+    }) => {
+      if (data.roomId === roomId) {
+        setRoomData((prev) => {
+          if (!prev) return null
+          return {
+            ...prev,
+            members: data.members,
+            memberPlayers: data.memberPlayers,
+          }
+        })
+      }
+    }
+
+    const handleRoomPlayersUpdated = (data: {
+      roomId: string
+      memberPlayers: Record<string, RoomPlayer[]>
+    }) => {
+      if (data.roomId === roomId) {
+        setRoomData((prev) => {
+          if (!prev) return null
+          return {
+            ...prev,
+            memberPlayers: data.memberPlayers,
+          }
+        })
+      }
+    }
+
+    socket.on('member-joined', handleMemberJoined)
+    socket.on('member-left', handleMemberLeft)
+    socket.on('room-players-updated', handleRoomPlayersUpdated)
+
+    return () => {
+      socket.off('member-joined', handleMemberJoined)
+      socket.off('member-left', handleMemberLeft)
+      socket.off('room-players-updated', handleRoomPlayersUpdated)
+    }
+  }, [socket, roomId])
+
+  return {
+    roomData,
+    isLoading,
+    isInRoom: !!roomId,
+  }
+}