feat: Warn user on startup if a mixed v1/v2 install is detected

We get frequent reports for users - in particular on the portable
version - who just mix v1 and v2 files. Since this causes incompatible
localization files to be merged, SyncTrayzor eventually crashes. This
upgrade procedure has never been supported by SyncTrayzor, but it likely
worked reasonably well enough in the past.

Warn if this is detected and instruct users to clean their install.

We also sometimes get reports of users on the installed version hitting
this problem. However, the v2 installer should remove v1 files, so it is
unclear why the installed version is sometimes affected by this as well.
A possibility is that it is caused by v1 files being locked by a stuck
v1 exe. In this case users also likely need to retry the installation.

Author: GermanCoding

src/SyncTrayzor/Bootstrapper.cs

@@ -78,6 +78,7 @@ protected override void ConfigureIoC(IStyletIoCBuilder builder)
             builder.Bind<IPathTransformer>().To<PathTransformer>().InSingletonScope();
             builder.Bind<IConnectedEventDebouncer>().To<ConnectedEventDebouncer>();
             builder.Bind<IDonationManager>().To<DonationManager>().InSingletonScope();
+            builder.Bind<IInstallationHealthCheck>().To<InstallationHealthCheck>().InSingletonScope();
 
             if (AppSettings.Instance.Variant == SyncTrayzorVariant.Installed)
                 builder.Bind<IUpdateVariantHandler>().To<InstalledUpdateVariantHandler>();
@@ -233,6 +234,8 @@ protected override void Configure()
             {
                 RenderOptions.ProcessRenderMode = RenderMode.SoftwareOnly;
             }
+
+            Container.Get<IInstallationHealthCheck>().CheckOutdatedV1Installation();
         }
 
         protected override void Launch()

src/SyncTrayzor/Services/InstallationHealthCheck.cs

@@ -0,0 +1,26 @@
+using System;
+using System.IO;
+using Stylet;
+
+namespace SyncTrayzor.Services;
+
+public interface IInstallationHealthCheck
+{
+    void CheckOutdatedV1Installation();
+}
+
+public class InstallationHealthCheck(IWindowManager windowManager) : IInstallationHealthCheck
+{
+    public void CheckOutdatedV1Installation()
+    {
+        var programDirectory = AppDomain.CurrentDomain.BaseDirectory;
+        var v1File = Path.Combine(programDirectory, "Pri.LongPath.dll");
+        if (File.Exists(v1File))
+        {
+            windowManager.ShowMessageBox(
+                "It looks like this SyncTrayzor installation contains files from SyncTrayzor v1. This will likely cause SyncTrayzor to crash. Please uninstall and re-install SyncTrayzor to remove v1 installation files. If you are running the portable version, you can move the \"data\" folder from your existing install to keep user data.",
+                "Mixed v1/v2 Installation Detected", System.Windows.MessageBoxButton.OK,
+                System.Windows.MessageBoxImage.Warning);
+        }
+    }
+}