refactor(launcher): reorganize into responsibility folders

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

LanMountainDesktop.Launcher/Oobe/WelcomeOobeStep.cs

@@ -0,0 +1,50 @@
+using Avalonia.Threading;
+using LanMountainDesktop.Launcher.Views;
+
+namespace LanMountainDesktop.Launcher.Oobe;
+
+internal sealed class WelcomeOobeStep : IOobeStep
+{
+    private readonly CommandContext _context;
+    private readonly OobeStateService _oobeStateService;
+
+    public WelcomeOobeStep(OobeStateService oobeStateService, CommandContext context)
+    {
+        _oobeStateService = oobeStateService;
+        _context = context;
+    }
+
+    public async Task RunAsync(CancellationToken cancellationToken)
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+
+        OobeWindow? window = null;
+        await Dispatcher.UIThread.InvokeAsync(() =>
+        {
+            window = new OobeWindow();
+            window.Show();
+        });
+
+        if (window is null)
+        {
+            return;
+        }
+
+        await window.WaitForEnterAsync().ConfigureAwait(false);
+        var completion = _oobeStateService.MarkCompleted(_context);
+        if (!completion.Success)
+        {
+            Logger.Warn(
+                $"OOBE completion state was not persisted. ResultCode='{completion.ResultCode}'; " +
+                $"Error='{completion.ErrorMessage}'.");
+        }
+
+        await Dispatcher.UIThread.InvokeAsync(() =>
+        {
+            if (window.IsVisible)
+            {
+                window.Close();
+            }
+        });
+    }
+}