fix: Windows 下 Claude 进程和 taskkill 不再弹出 CMD 窗口

- spawn 改为 detached: !IS_WIN（Windows 子进程默认独立存活，无需 detached）
- taskkill 增加 stdio: 'ignore' 防止弹窗

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

server.js

@@ -300,7 +300,7 @@ function killProcess(pid, force = false) {
     if (IS_WIN) {
       const args = ['/T', '/PID', String(pid)];
       if (force) args.unshift('/F');
-      spawn('taskkill', args, { windowsHide: true });
+      spawn('taskkill', args, { windowsHide: true, stdio: 'ignore' });
     } else {
       process.kill(pid, force ? 'SIGKILL' : 'SIGTERM');
     }
@@ -1077,7 +1077,7 @@ function handleMessage(ws, msg) {
       env,
       cwd: process.env.HOME || process.env.USERPROFILE || process.cwd(),
       stdio: [inputFd, outputFd, errorFd],
-      detached: true,
+      detached: !IS_WIN,
       windowsHide: true,
     });
   } catch (err) {