fix: use TextBlock instead of SelectableTextBlock in toolbar buttons

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: sharpninja

src/McpServerManager.Desktop/Views/ChatWindow.axaml

@@ -25,10 +25,10 @@
                 <ComboBox Grid.Column="1" ItemsSource="{Binding AvailableModels}" SelectedItem="{Binding SelectedModel}"
                           MinWidth="180" HorizontalAlignment="Left" FontSize="14"/>
                 <Button Grid.Column="2" Command="{Binding OpenAgentConfigCommand}" Margin="8,0,0,0" ToolTip.Tip="Open agent config in default editor">
-                    <SelectableTextBlock Text="Agent config" FontSize="12"/>
+                    <TextBlock Text="Agent config" FontSize="12"/>
                 </Button>
                 <Button Grid.Column="3" Command="{Binding OpenPromptTemplatesCommand}" Margin="4,0,0,0" ToolTip.Tip="Open prompt templates in default editor">
-                    <SelectableTextBlock Text="Prompts" FontSize="12"/>
+                    <TextBlock Text="Prompts" FontSize="12"/>
                 </Button>
             </Grid>
         </Border>

src/McpServerManager/Views/ChatWindow.axaml

@@ -28,10 +28,10 @@
                 <ComboBox Grid.Column="1" ItemsSource="{Binding AvailableModels}" SelectedItem="{Binding SelectedModel}"
                           MinWidth="180" HorizontalAlignment="Left" FontSize="14"/>
                 <Button Grid.Column="2" Command="{Binding OpenAgentConfigCommand}" Margin="8,0,0,0" ToolTip.Tip="Open agent config in default editor">
-                    <SelectableTextBlock Text="Agent config" FontSize="12"/>
+                    <TextBlock Text="Agent config" FontSize="12"/>
                 </Button>
                 <Button Grid.Column="3" Command="{Binding OpenPromptTemplatesCommand}" Margin="4,0,0,0" ToolTip.Tip="Open prompt templates in default editor">
-                    <SelectableTextBlock Text="Prompts" FontSize="12"/>
+                    <TextBlock Text="Prompts" FontSize="12"/>
                 </Button>
             </Grid>
         </Border>