Fix Windows auto-update to replace Navis.exe in place (1.8.1).

Co-authored-by: Cursor <cursoragent@cursor.com>

cmd/vpnapp/main_windows.go

@@ -61,6 +61,7 @@ func main() {
 	if update.MaybeFinishUpdate(os.Args[1:]) {
 		return
 	}
+	update.CleanupStaleDownloads()
 
 	log.SetFlags(log.LstdFlags | log.Lshortfile)
 
@@ -342,11 +343,9 @@ func (a *app) applyUpdate() (string, error) {
 		return "", err
 	}
 	_ = a.mgr.Disconnect()
+	// Hard-exit so Windows unlocks Navis.exe; do not wait on webview.Terminate (can hang).
 	go func() {
-		time.Sleep(400 * time.Millisecond)
-		if a.webview != nil {
-			a.webview.Terminate()
-		}
+		time.Sleep(300 * time.Millisecond)
 		os.Exit(0)
 	}()
 	return "Устанавливается v" + latest + "… Navis перезапустится.", nil