fix: Dialog_Notice/MsgBox MessageBox options arg - invalid HelpButton value

Previous topmost attempt passed 'HelpButton' in the MessageBoxOptions position of
MessageBox::Show, so PowerShell failed at runtime with "cannot convert value
HelpButton to type System.Windows.Forms.MessageBoxOptions" (reproduced in flow run:
notice node failed at char 196). Now passes the documented MB_TOPMOST flag
(MessageBoxOptions)262144 as the 6th argument, keeping the six-argument overload
(OK / Information / Button1 / topmost).

packages/rpa-core/src/capabilities/desktop.ts

@@ -154,7 +154,9 @@ const notice: CapabilityHandler = async (_ctx, _node, args) => {
   // MessageBox 阻塞等用户点确定，同样不能吃 powershell() 默认 30s 超时；且 MB_TOPMOST 保证弹窗不被主窗口盖住
   const waitSeconds = number(args, ["wait_time", "waitTime", "timeout"], 600);
   const timeoutMs = Math.max(10000, Math.round(waitSeconds * 1000));
-  await powershell(`Add-Type -AssemblyName System.Windows.Forms; [System.Windows.Forms.MessageBox]::Show(${psString(content)},${psString(title)},'OK','Information','Button1','HelpButton',1) | Out-Null`, timeoutMs);
+  // MessageBoxOptions 第 6 参数用 MB_TOPMOST(0x40000=262144) 标志位实现置顶；此前误传 'HelpButton'（图标枚举值）
+  // 导致 PowerShell 类型转换失败「无法将 HelpButton 转换为 MessageBoxOptions」
+  await powershell(`Add-Type -AssemblyName System.Windows.Forms; [System.Windows.Forms.MessageBox]::Show(${psString(content)},${psString(title)},'OK','Information','Button1',[System.Windows.Forms.MessageBoxOptions]262144) | Out-Null`, timeoutMs);
   return true;
 };