use ACT_LABELS from shared constants in room header

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

packages/client/src/components/room-header.tsx

@@ -1,4 +1,5 @@
 import { Badge } from "@/components/ui/badge"
+import { ACT_LABELS } from "@celebrate-esc/shared"
 import type { Act } from "@celebrate-esc/shared"
 
 interface RoomHeaderProps {
@@ -7,20 +8,12 @@ interface RoomHeaderProps {
 	connectionStatus: "disconnected" | "connecting" | "connected"
 }
 
-const actLabels: Record<Act, string> = {
-	lobby: "Lobby",
-	act1: "Act 1",
-	act2: "Act 2",
-	act3: "Act 3",
-	ended: "Ended",
-}
-
 export function RoomHeader({ roomCode, currentAct, connectionStatus }: RoomHeaderProps) {
 	return (
 		<div className="flex items-center justify-between border-b p-4">
 			<div className="flex items-center gap-3">
 				<span className="font-mono text-2xl font-bold tracking-widest">{roomCode}</span>
-				<Badge variant="outline">{actLabels[currentAct]}</Badge>
+				<Badge variant="outline">{ACT_LABELS[currentAct]}</Badge>
 			</div>
 			<span
 				className={`h-2 w-2 rounded-full ${