Add unready toggle in lobby

- Server: Handle unready event to set player ready state to false
- Client: Ready button toggles between READY and UNREADY
- Client: Unready sends unready socket event to server

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

server/index.js

@@ -118,6 +118,19 @@ io.on('connection', (socket) => {
     }
   });
 
+  socket.on('unready', () => {
+    const player = lobby.players.get(socket.id);
+    if (!player) return;
+
+    player.ready = false;
+
+    // Broadcast only to players in the lobby room
+    io.to(LOBBY_ROOM).emit('player-joined', {
+      player: { id: player.id, name: player.name, ready: player.ready },
+      players: getPlayersList()
+    });
+  });
+
   socket.on('player-move', ({ playerId, direction }) => {
     if (!lobby.gameStarted) return;
 
@@ -367,14 +380,12 @@ function clearRows(player) {
 }
 
 function sendGarbage(sender, rowsCleared) {
-  const garbageRows = rowsCleared >= 4 ? rowsCleared : Math.max(1, rowsCleared - 1);
+  // Number of garbage rows equals number of lines cleared
   const opponents = Array.from(lobby.players.values()).filter(p => p.id !== sender.id && !p.eliminated);
   if (opponents.length === 0) return;
-  // Send all garbage rows to each opponent
-  for (const opponent of opponents) {
-    for (let i = 0; i < garbageRows; i++) {
-      addGarbageToPlayer(opponent);
-    }
+  for (let i = 0; i < rowsCleared; i++) {
+    const target = opponents[Math.floor(Math.random() * opponents.length)];
+    addGarbageToPlayer(target);
   }
 }