add QR code to display view lobby screen

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/client/package.json

@@ -17,6 +17,7 @@
 		"class-variance-authority": "^0.7.1",
 		"clsx": "^2.1.1",
 		"lucide-react": "^0.577.0",
+		"qrcode.react": "^4.2.0",
 		"react": "latest",
 		"react-dom": "latest",
 		"tailwind-merge": "^3.5.0",

packages/client/src/routes/display.$roomCode.tsx

@@ -1,4 +1,5 @@
 import { useState } from "react"
+import { QRCodeSVG } from "qrcode.react"
 import { createFileRoute } from "@tanstack/react-router"
 import { useWebSocket } from "@/hooks/use-websocket"
 import { useRoomStore } from "@/stores/room-store"
@@ -158,6 +159,7 @@ function LobbyDisplay({ roomCode }: { roomCode: string }) {
 					<>Tap the code to copy</>
 				)}
 			</p>
+			<QRCodeSVG value={joinUrl} size={192} level="M" />
 			<p className="text-muted-foreground">
 				Go to <span className="font-mono font-medium">{joinUrl}</span>
 			</p>