feat: sistema de 2 rondas con puntos dobles

Ronda 1: 5 categorías con puntos normales (100-500)
Ronda 2: 5 categorías diferentes con puntos x2 (200-1000)

Backend:
- question_service: soporta excluir categorías y multiplicador de puntos
- game_manager: trackea current_round, start_round_2() carga nuevo tablero
- game_events: emite round_started al completar ronda 1

Frontend:
- useSocket: escucha evento round_started
- Game.tsx: muestra indicador de ronda actual
- types: GameRoom incluye current_round

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/hooks/useSocket.ts

@@ -85,6 +85,14 @@ export function useSocket() {
       soundPlayer.play('game_start', volume)
     })
 
+    socket.on('round_started', (data: { room: GameRoom; round: number; message: string }) => {
+      setRoom(data.room)
+      setCurrentQuestion(null)
+      // Play sound for new round
+      const volume = useSoundStore.getState().volume
+      soundPlayer.play('game_start', volume)
+    })
+
     socket.on('question_selected', (data: { room: GameRoom; question_id: number }) => {
       setRoom(data.room)
       // Find the question in the board and set it as current

frontend/src/pages/Game.tsx

@@ -157,7 +157,7 @@ export default function Game() {
   return (
     <div className="min-h-screen p-2 md:p-4 overflow-hidden" style={styles.bgPrimary}>
       <div className="max-w-7xl mx-auto">
-        {/* Header with Room Code */}
+        {/* Header with Room Code and Round */}
         <div className="text-center mb-4">
           <motion.h1
             initial={{ y: -20, opacity: 0 }}
@@ -167,8 +167,21 @@ export default function Game() {
           >
             TRIVY
           </motion.h1>
-          <div className="text-xs opacity-60" style={{ color: config.colors.textMuted }}>
-            Sala: {room.code}
+          <div className="flex items-center justify-center gap-3 text-xs" style={{ color: config.colors.textMuted }}>
+            <span className="opacity-60">Sala: {room.code}</span>
+            <span className="opacity-40">|</span>
+            <motion.span
+              key={room.current_round}
+              initial={{ scale: 1.5, color: config.colors.accent }}
+              animate={{ scale: 1, color: config.colors.textMuted }}
+              className="font-bold"
+              style={{
+                color: room.current_round === 2 ? config.colors.accent : config.colors.textMuted
+              }}
+            >
+              Ronda {room.current_round || 1}
+              {room.current_round === 2 && ' (x2)'}
+            </motion.span>
           </div>
         </div>
 

frontend/src/types/index.ts

@@ -45,6 +45,7 @@ export interface GameRoom {
   can_steal: boolean
   scores: { A: number; B: number }
   board: Record<string, Question[]>
+  current_round?: number
 }
 
 export interface ChatMessage {