feat(launcher): show the window when Wand fails to start

Launch mode pushes its log into the UI and opens it on failure instead of
leaving only launcher.log. Exit codes of Wand child processes are read
again by keeping their handles, which the job object does not carry.

WandEnhancer/Program.cs

@@ -28,9 +28,18 @@ namespace WandEnhancer
             AppDomain.CurrentDomain.UnhandledException += OnUnhandledException;
             TaskScheduler.UnobservedTaskException += OnUnobservedTaskException;
 
+            bool startupFailed = StartupLog.Exists(entry => entry.Value == ELogType.Error);
+
             var application = new App();
             application.InitializeComponent();
-            application.MainWindow = new MainWindow();
+            var window = new MainWindow();
+
+            // Launch mode has no window at all, so a user whose Wand never opened would have to
+            // be told where launcher.log lives. Put the same lines in front of them instead.
+            if (startupFailed)
+                window.Loaded += (sender, e) => BringToFront(window);
+
+            application.MainWindow = window;
             application.Run();
         }
 
@@ -82,14 +91,21 @@ namespace WandEnhancer
             if (!isPatched && !TryAutoPatch(config, myDir))
                 return false;
 
-            FuseLauncher.Launch(config.ExecutablePath, forwardedArgs, LauncherLog.Write);
-            return true;
+            // RecordStartupLog, not LauncherLog.Write: whatever the launcher says has to survive
+            // into the window on the failure path below.
+            return FuseLauncher.Launch(config.ExecutablePath, forwardedArgs, RecordStartupLog);
         }
 
-        /// <summary>
-        /// Re-quotes argv for a command line. Squirrel hands us paths with spaces
-        /// (`--squirrel-install "C:\Users\Some Name\..."`); re-joining on spaces splits them.
-        /// </summary>
+
+        private static void BringToFront(System.Windows.Window window)
+        {
+            window.WindowState = System.Windows.WindowState.Normal;
+            window.Topmost = true;
+            window.Activate();
+            window.Topmost = false;
+        }
+
+
         private static string QuoteArguments(IEnumerable<string> args)
         {
             return string.Join(" ", args.Select(QuoteArgument));