Fix updater static init order; clear staged updates on startup

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

Services/UpdateService.cs

@@ -15,6 +15,8 @@ public static class UpdateService
     public static string Repo { get; } = Environment.GetEnvironmentVariable("CVRMANAGER_UPDATE_REPO") is { Length: > 0 } r ? r : "Koneko/CVRManager";
     public const string AssetName = "CVRManager-win-x64.zip";
 
+    public static Version Current { get; } = Normalize(Assembly.GetEntryAssembly()?.GetName().Version ?? new Version(1, 0, 0));
+
     static readonly HttpClient Http = CreateClient();
 
     static HttpClient CreateClient()
@@ -24,8 +26,6 @@ public static class UpdateService
         return http;
     }
 
-    public static Version Current { get; } = Normalize(Assembly.GetEntryAssembly()?.GetName().Version ?? new Version(1, 0, 0));
-
     static Version Normalize(Version v) => new(v.Major, Math.Max(v.Minor, 0), Math.Max(v.Build, 0));
 
     public static bool TryParseTag(string tag, out Version version)

ViewModels/MainViewModel.cs

@@ -841,6 +841,7 @@ public class MainViewModel : ObservableObject
             RebuildChoices();
         }
         _ = RefreshBranchesQuietAsync(CancellationToken.None);
+        _ = Task.Run(() => { try { Directory.Delete(Path.Combine(Paths.Root, "update"), true); } catch (Exception e) when (e is IOException or UnauthorizedAccessException) { } });
         if (cfg.CheckUpdates) _ = CheckForUpdateAsync(false);
         if (!IsBusy) await RefreshModCoreAsync(MelonLoader, quiet: true);
         _ = Task.Run(() =>