fix: keep MCP transport alive when stdin closes

src/server.js

@@ -1112,9 +1112,12 @@ rl.on('line', async (line) => {
 
 /** Cursor 可能关闭 MCP stdin；挂起 poll 期间禁止 exit，否则 Hub 仍 waiting 但无 poller */
 let activeWaitToken = null;
+let idleKeepAliveTimer = null;
 process.stdin.on('end', () => {
   log('stdin end', { activeWait: activeWaitToken });
-  if (!activeWaitToken) setTimeout(() => process.exit(0), 200);
+  if (activeWaitToken) return;
+  if (!idleKeepAliveTimer) idleKeepAliveTimer = setInterval(() => {}, 60 * 1000);
+  log('stdin end ignored: keep alive while idle to preserve transport');
 });
 
 process.on('SIGTERM', () => process.exit(0));