[KBM] Fix Action panel not showing for Text Expand trigger type

Replace XAML binding on SwitchPresenter.Value with code-behind sync
to avoid binding/direct-assignment conflict when ComboBox items are
dynamically replaced for the Expand trigger type.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: Yu Leng (from Dev Box)

src/modules/keyboardmanager/KeyboardManagerEditorUI/Controls/UnifiedMappingControl.xaml

@@ -265,7 +265,7 @@
             <tkcontrols:SwitchPresenter
                 x:Name="ActionSwitchPresenter"
                 TargetType="x:String"
-                Value="{Binding SelectedItem.Tag, ElementName=ActionTypeComboBox}">
+                Value="KeyOrShortcut">
                 <!--  Key or Shortcut Action  -->
                 <tkcontrols:Case Value="KeyOrShortcut">
                     <ToggleButton

src/modules/keyboardmanager/KeyboardManagerEditorUI/Controls/UnifiedMappingControl.xaml.cs

@@ -258,6 +258,12 @@ private void ActionTypeComboBox_SelectionChanged(object sender, SelectionChanged
             {
                 string? tag = item.Tag?.ToString();
 
+                // Sync SwitchPresenter with the selected action type
+                if (tag != null && ActionSwitchPresenter != null)
+                {
+                    ActionSwitchPresenter.Value = tag;
+                }
+
                 // Cleanup keyboard hook when switching away from key/shortcut
                 if (tag != "KeyOrShortcut")
                 {