Add overall progress, notifications, and UI polish

- Unify audio/subtitle selection: single-select, auto-default,
  cross-file propagation by exact name
- Show file size in queue, group divider and reordered columns in
  track table, drop accent highlight on row selection
- Add cumulative progress bar (files finished, MB copied) to the
  stripping window
- Add Windows toast notifications on stripping completion/cancel/error
- Restart the app after settings are changed; Cancel no longer
  clears the queue, only closes the window
- Add ConfigureAwait(false) throughout MkvService so concurrent
  strips don't starve the UI thread
- Hardcode scan/strip concurrency (10/5) instead of exposing it in
  Settings

Views/ProgressWindow.xaml

@@ -24,6 +24,7 @@
                 <RowDefinition Height="Auto"/>
                 <RowDefinition Height="*"/>
                 <RowDefinition Height="Auto"/>
+                <RowDefinition Height="Auto"/>
             </Grid.RowDefinitions>
 
             <!-- Active jobs -->
@@ -53,8 +54,25 @@
                             BorderThickness="0" Background="Transparent"/>
             </Border>
 
-            <!-- Status + speed + button -->
+            <!-- Total progress -->
             <Grid Grid.Row="2" Margin="0,10,0,0">
+                <Grid.RowDefinitions>
+                    <RowDefinition Height="Auto"/>
+                    <RowDefinition Height="Auto"/>
+                </Grid.RowDefinitions>
+                <ProgressBar x:Name="TotalProgressBar" Grid.Row="0" Height="8" Minimum="0" Maximum="100" Value="0"/>
+                <Grid Grid.Row="1" Margin="0,4,0,0">
+                    <Grid.ColumnDefinitions>
+                        <ColumnDefinition Width="*"/>
+                        <ColumnDefinition Width="Auto"/>
+                    </Grid.ColumnDefinitions>
+                    <TextBlock x:Name="TotalFilesText" Grid.Column="0" FontSize="11" Opacity="0.75"/>
+                    <TextBlock x:Name="TotalBytesText" Grid.Column="1" FontSize="11" Opacity="0.75"/>
+                </Grid>
+            </Grid>
+
+            <!-- Status + speed + button -->
+            <Grid Grid.Row="3" Margin="0,10,0,0">
                 <Grid.ColumnDefinitions>
                     <ColumnDefinition Width="*"/>
                     <ColumnDefinition Width="Auto"/>