Remove client-side game over check to prevent premature game end

The client was checking activePlayers.length <= 1 and calling endGame()
prematurely, before the server's authoritative game-over event.

Now the client only ends the game when the server explicitly sends the
'game-over' event.

Added server-side logging to track active player count and winner.

server/index.js

@@ -590,7 +590,9 @@ function getStates() {
 
 function checkGameOver() {
   const activePlayers = Array.from(lobby.players.values()).filter(p => !p.eliminated);
+  console.log(`[GAMEOVER CHECK] Active players: ${activePlayers.length} (${activePlayers.map(p => p.name).join(', ')})`);
   if (activePlayers.length <= 1) {
+    console.log(`[GAME OVER] ${activePlayers.length === 1 ? `Winner: ${activePlayers[0].name}` : 'No winner (all eliminated)'}`);
     io.to(LOBBY_ROOM).emit('game-over', { states: getStates() });
     if (lobby.gameInterval) {
       clearInterval(lobby.gameInterval);