Add manual X close to toast notification

Toast was auto-dismiss-only (3s timer). Operators running a live show want to clear visual clutter without waiting — added a small X button to the right of the message that calls ToastViewModel.DismissCommand (stops timer + hides immediately).

Implementation: ToastViewModel gained a DismissCommand RelayCommand and a Hide() helper. MainWindow toast overlay gained a 20x20 button bound to the command, custom inline template (rounded transparent bg, hover lifts to Wd.Button.HoverBg).

src/TeamsISO.App/MainWindow.xaml

@@ -997,7 +997,9 @@
                     </Grid>
                 </Border>
 
-                <!-- Toast overlay: bottom-center, auto-dismissing transient notification. -->
+                <!-- Toast overlay: bottom-center, auto-dismissing transient notification.
+                     Manual X dismiss for operators running a live show who want
+                     to clear visual clutter without waiting the 3s auto-hide. -->
                 <Border Grid.Row="2"
                         VerticalAlignment="Bottom"
                         HorizontalAlignment="Center"
@@ -1006,7 +1008,7 @@
                         BorderBrush="{DynamicResource Wd.BorderStrong}"
                         BorderThickness="1"
                         CornerRadius="999"
-                        Padding="14,8"
+                        Padding="14,6,8,6"
                         Visibility="{Binding Toast.IsVisible, Converter={StaticResource BoolToVis}}">
                     <StackPanel Orientation="Horizontal">
                         <Ellipse Width="8" Height="8"
@@ -1015,8 +1017,36 @@
                         <TextBlock Text="{Binding Toast.Message}"
                                    Style="{StaticResource Wd.Text.Body}"
                                    FontSize="12"
-                                   Margin="10,0,0,0"
+                                   Margin="10,0,12,0"
                                    VerticalAlignment="Center"/>
+                        <Button Command="{Binding Toast.DismissCommand}"
+                                Width="20" Height="20"
+                                Background="Transparent"
+                                BorderThickness="0"
+                                Cursor="Hand"
+                                FocusVisualStyle="{x:Null}"
+                                ToolTip="Dismiss this toast">
+                            <Button.Template>
+                                <ControlTemplate TargetType="Button">
+                                    <Border x:Name="Bd"
+                                            Background="{TemplateBinding Background}"
+                                            CornerRadius="10">
+                                        <Path Data="M 0,0 L 8,8 M 8,0 L 0,8"
+                                              Stroke="{DynamicResource Wd.Text.Tertiary}"
+                                              StrokeThickness="1.2"
+                                              Width="8" Height="8"
+                                              Stretch="None"
+                                              HorizontalAlignment="Center"
+                                              VerticalAlignment="Center"/>
+                                    </Border>
+                                    <ControlTemplate.Triggers>
+                                        <Trigger Property="IsMouseOver" Value="True">
+                                            <Setter TargetName="Bd" Property="Background" Value="{DynamicResource Wd.Button.HoverBg}"/>
+                                        </Trigger>
+                                    </ControlTemplate.Triggers>
+                                </ControlTemplate>
+                            </Button.Template>
+                        </Button>
                     </StackPanel>
                 </Border>
             </Grid>

src/TeamsISO.App/ViewModels/ToastViewModel.cs

@@ -1,3 +1,4 @@
+using System.Windows.Input;
 using System.Windows.Threading;
 
 namespace TeamsISO.App.ViewModels;
@@ -27,6 +28,21 @@ public sealed class ToastViewModel : ObservableObject
             _hideTimer.Stop();
             IsVisible = false;
         };
+        DismissCommand = new RelayCommand(Hide);
+    }
+
+    /// <summary>
+    /// Manual dismiss. Stops the auto-hide timer and hides the toast
+    /// immediately. Bound to the X close button on the toast overlay so an
+    /// operator running a live show can clear visual clutter without waiting
+    /// 3 seconds.
+    /// </summary>
+    public ICommand DismissCommand { get; }
+
+    private void Hide()
+    {
+        _hideTimer.Stop();
+        IsVisible = false;
     }
 
     public string Message