feat: 增加钻带涨缩功能，支持倍率/PPM模式缩放坐标

- 新增 ExcellonScaler 引擎：普通孔缩放坐标，G85槽孔保护槽长，刀具定义行原样保留
- 新增 DrillScalingWindow 参数设置窗口：倍率/PPM模式切换，X/Y独立输入
- 集成到启动功能菜单：.dr2/.dpin 文件显示"涨缩"按钮
- 输出覆盖原文件 + .bak 备份，GB2312 编码

DrillScalingWindow.xaml.cs

@@ -0,0 +1,57 @@
+using System.Windows;
+
+namespace DrillTools
+{
+    /// <summary>
+    /// 钻带涨缩参数设置窗口
+    /// </summary>
+    public partial class DrillScalingWindow : Window
+    {
+        private readonly DrillScalingViewModel _viewModel;
+
+        /// <summary>
+        /// 用户确认后的缩放结果（kx, ky）
+        /// </summary>
+        public (double Kx, double Ky)? ScalingResult { get; private set; }
+
+        public DrillScalingWindow()
+        {
+            InitializeComponent();
+            _viewModel = new DrillScalingViewModel();
+            DataContext = _viewModel;
+        }
+
+        private void ModeRadioButton_Changed(object sender, RoutedEventArgs e)
+        {
+            if (_viewModel == null)
+                return;
+
+            if (RatioRadioButton.IsChecked == true)
+                _viewModel.Mode = ScalingMode.Ratio;
+            else if (PpmRadioButton.IsChecked == true)
+                _viewModel.Mode = ScalingMode.Ppm;
+        }
+
+        private void ExecuteButton_Click(object sender, RoutedEventArgs e)
+        {
+            var error = _viewModel.Validate();
+            if (error != null)
+            {
+                ErrorText.Text = error;
+                ErrorText.Visibility = Visibility.Visible;
+                return;
+            }
+
+            ScalingResult = (_viewModel.Kx, _viewModel.Ky);
+            DialogResult = true;
+            Close();
+        }
+
+        private void CancelButton_Click(object sender, RoutedEventArgs e)
+        {
+            ScalingResult = null;
+            DialogResult = false;
+            Close();
+        }
+    }
+}