fix: flush CLI stdio before forced exit

src/cli.ts

@@ -380,6 +380,9 @@ function flushWriteStream(stream: NodeJS.WriteStream, timeoutMs: number): Promis
   if (!stream.writable || stream.destroyed || stream.writableEnded) {
     return Promise.resolve();
   }
+  if (stream.writableLength === 0 && !stream.writableNeedDrain) {
+    return Promise.resolve();
+  }
 
   return new Promise((resolve) => {
     let settled = false;

tests/cli-force-exit-behavior.integration.test.ts

@@ -50,6 +50,10 @@ const [cliEntry, configPath] = process.argv.slice(2);
 process.env.MCPORTER_DISABLE_AUTORUN = '1';
 
 let cleanupWriteSeen = false;
+Object.defineProperty(process.stdout, 'writableNeedDrain', {
+  configurable: true,
+  get: () => true,
+});
 const originalWrite = process.stdout.write.bind(process.stdout);
 process.stdout.write = (chunk, encoding, callback) => {
   const done = typeof encoding === 'function' ? encoding : callback;