A socket's own error closes that socket, not the server

A message over the size limit or a malformed frame raised an error on
the socket, which had no listener, and Node ended the process: one
message from anyone could take the server down until systemd restarted
it. The socket is terminated instead.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Jm2auWk6RP71CjaAb4FMoG

packages/server/src/index.ts

@@ -738,6 +738,8 @@ wss.on("connection", (socket, req) => {
     roomsCreated: 0, lastCatchUpAt: 0, hotseatReports: 0,
   };
   sessions.add(session);
+  // A socket's own error (a frame over the limit, a malformed one) closes that socket, never the server.
+  socket.on("error", () => socket.terminate());
   send(socket, { type: "welcome", game: "wizwar" });
 
   socket.on("close", () => {