feat: Add solo mode functionality to repository toolbar

- Add a new localization string for solo mode functionality on HEAD.
- Add a solo mode button to the repository toolbar for toggling the current head view.
- Add solo commit filter mode for the current HEAD branch.

Author: heartacker

src/Resources/Locales/en_US.axaml

@@ -655,6 +655,7 @@
   <x:String x:Key="Text.Repository.LocalBranches" xml:space="preserve">LOCAL BRANCHES</x:String>
   <x:String x:Key="Text.Repository.MoreOptions" xml:space="preserve">More options...</x:String>
   <x:String x:Key="Text.Repository.NavigateToCurrentHead" xml:space="preserve">Navigate to HEAD</x:String>
+  <x:String x:Key="Text.Repository.SoloModeOnCurrentHead" xml:space="preserve">Solo On HEAD</x:String>
   <x:String x:Key="Text.Repository.NewBranch" xml:space="preserve">Create Branch</x:String>
   <x:String x:Key="Text.Repository.Notifications.Clear" xml:space="preserve">CLEAR NOTIFICATIONS</x:String>
   <x:String x:Key="Text.Repository.OnlyHighlightCurrentBranchInGraph" xml:space="preserve">Only highlight current branch</x:String>

src/Views/RepositoryToolbar.axaml

@@ -132,6 +132,9 @@
       <Button Classes="icon_button" Width="32" Click="NavigateToHead" ToolTip.Tip="{DynamicResource Text.Repository.NavigateToCurrentHead}">
         <Path Width="13" Height="13" Margin="0,2,0,0" Data="{StaticResource Icons.Target}" Fill="{DynamicResource Brush.FG1}"/>
       </Button>
+      <Button Classes="icon_button" Width="32" Click="SoloModeOnCurrentHead" ToolTip.Tip="{DynamicResource Text.Repository.SoloModeOnCurrentHead}">
+        <Path Width="13" Height="13" Margin="0,2,0,0" Data="{StaticResource Icons.LightOn}" Fill="{DynamicResource Brush.FG1}"/>
+      </Button>
     </StackPanel>
   </Grid>
 </UserControl>

src/Views/RepositoryToolbar.axaml.cs

@@ -462,5 +462,14 @@ private void NavigateToHead(object sender, RoutedEventArgs e)
                 e.Handled = true;
             }
         }
+
+        private void SoloModeOnCurrentHead(object sender, RoutedEventArgs e)
+        {
+            if (DataContext is ViewModels.Repository { CurrentBranch: not null } repo)
+            {
+                repo.SetSoloCommitFilterMode(repo.CurrentBranch.Head[..10], Models.FilterMode.Included);
+                e.Handled = true;
+            }
+        }
     }
 }