Add an option to check for update without proxy (#10090)

Checking for updates always dialed through the local proxy, which fails
exactly when an update may be needed most - when no working server is
available. Like the subscription-update menu, updating without the proxy
is now possible: the Check Update window gets an "Update via proxy"
toggle (persisted, on by default so existing behavior is unchanged),
honored by the check-only, update and geo-file flows, and by the
scheduled update check.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

v2rayN/v2rayN.Desktop/Views/CheckUpdateView.axaml

@@ -25,6 +25,16 @@
                 HorizontalAlignment="Center"
                 Orientation="Horizontal">
 
+                <TextBlock
+                    Margin="{StaticResource Margin4}"
+                    HorizontalAlignment="Left"
+                    VerticalAlignment="Center"
+                    Text="{x:Static resx:ResUI.TbSettingsEnableUpdateViaProxy}" />
+                <ToggleSwitch
+                    x:Name="togEnableUpdateViaProxy"
+                    Margin="{StaticResource Margin4}"
+                    HorizontalAlignment="Left" />
+
                 <TextBlock
                     Margin="{StaticResource Margin4}"
                     HorizontalAlignment="Left"

v2rayN/v2rayN.Desktop/Views/CheckUpdateView.axaml.cs

@@ -11,6 +11,7 @@ public partial class CheckUpdateView : ReactiveUserControl<CheckUpdateViewModel>
             this.OneWayBind(ViewModel, vm => vm.CheckUpdateModels, v => v.lstCheckUpdates.ItemsSource).DisposeWith(disposables);
 
             this.Bind(ViewModel, vm => vm.EnableCheckPreReleaseUpdate, v => v.togEnableCheckPreReleaseUpdate.IsChecked).DisposeWith(disposables);
+            this.Bind(ViewModel, vm => vm.EnableUpdateViaProxy, v => v.togEnableUpdateViaProxy.IsChecked).DisposeWith(disposables);
             this.BindCommand(ViewModel, vm => vm.CheckOnlyCmd, v => v.btnCheckOnly).DisposeWith(disposables);
             this.BindCommand(ViewModel, vm => vm.CheckUpdateCmd, v => v.btnCheckUpdate).DisposeWith(disposables);
         });