feat(installer): async mode detection + mode-aware DI wiring

src/ClaudeDo.Installer/App.xaml.cs

@@ -1,3 +1,6 @@
+using System.IO;
+using System.Net.Http;
+using System.Reflection;
 using System.Windows;
 using ClaudeDo.Installer.Core;
 using ClaudeDo.Installer.Pages.InstallPage;
@@ -15,16 +18,45 @@ public partial class App : Application
 {
     private ServiceProvider? _services;
 
-    protected override void OnStartup(StartupEventArgs e)
+    protected override async void OnStartup(StartupEventArgs e)
     {
         base.OnStartup(e);
 
         _services = BuildServices();
 
-        // TODO(Task 11): replace with async InstallModeDetector
+        var context = _services.GetRequiredService<InstallContext>();
-        Window mainWindow = new WizardWindow
+        context.InstallerVersion = GetInstallerVersion();
+
+        // Default install dir for detection — on upgrade we stay where we were.
+        var detector = _services.GetRequiredService<InstallModeDetector>();
+        var cts = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        DetectedState state;
+        try
         {
-            DataContext = _services.GetRequiredService<WizardViewModel>()
+            state = await detector.DetectAsync(context.InstallDirectory, cts.Token);
+        }
+        catch (OperationCanceledException)
+        {
+            state = new DetectedState(InstallerMode.FreshInstall, null, null, null);
+        }
+
+        context.Mode = state.Mode;
+        context.InstalledVersion = state.Existing?.Version;
+        context.LatestVersion = state.LatestVersion;
+        if (state.Existing is not null)
+            context.InstallDirectory = state.Existing.InstallDir;
+
+        Window mainWindow = state.Mode switch
+        {
+            InstallerMode.FreshInstall or InstallerMode.Update => new WizardWindow
+            {
+                DataContext = _services.GetRequiredService<WizardViewModel>()
+            },
+            InstallerMode.Config => new SettingsWindow
+            {
+                DataContext = _services.GetRequiredService<SettingsViewModel>()
+            },
+            _ => throw new InvalidOperationException($"Unknown installer mode: {state.Mode}")
         };
 
         DarkTitleBar.Apply(mainWindow);
@@ -37,6 +69,13 @@ public partial class App : Application
         base.OnExit(e);
     }
 
+    private static string GetInstallerVersion()
+    {
+        var infoAttr = Assembly.GetExecutingAssembly()
+            .GetCustomAttribute<AssemblyInformationalVersionAttribute>();
+        return infoAttr?.InformationalVersion ?? "0.0.0";
+    }
+
     private static ServiceProvider BuildServices()
     {
         var sc = new ServiceCollection();
@@ -46,6 +85,11 @@ public partial class App : Application
         sc.AddSingleton<PageResolver>();
         sc.AddSingleton<InstallerService>();
 
+        // HTTP + release client
+        sc.AddSingleton(_ => new HttpClient { Timeout = TimeSpan.FromSeconds(15) });
+        sc.AddSingleton<IReleaseClient>(sp => new ReleaseClient(sp.GetRequiredService<HttpClient>()));
+        sc.AddSingleton<InstallModeDetector>();
+
         // Pages
         sc.AddSingleton<IInstallerPage, WelcomePageViewModel>();
         sc.AddSingleton<IInstallerPage, PathsPageViewModel>();
@@ -53,11 +97,22 @@ public partial class App : Application
         sc.AddSingleton<IInstallerPage, UiSettingsPageViewModel>();
         sc.AddSingleton<IInstallerPage, InstallPageViewModel>();
 
-        // Steps (registration order = execution order)
+        // Steps — execution order matters for the FreshInstall pipeline (IEnumerable<IInstallStep>).
+        // Double-registered as both IInstallStep and concrete type so Task 15's Update pipeline
+        // can pull them out individually via GetRequiredService<T>().
+        sc.AddSingleton<DownloadAndExtractStep>();
+        sc.AddSingleton<IInstallStep>(sp => sp.GetRequiredService<DownloadAndExtractStep>());
         sc.AddSingleton<IInstallStep, WriteConfigStep>();
         sc.AddSingleton<IInstallStep, InitDatabaseStep>();
         sc.AddSingleton<IInstallStep, RegisterServiceStep>();
         sc.AddSingleton<IInstallStep, CreateShortcutsStep>();
+        sc.AddSingleton<WriteInstallManifestStep>();
+        sc.AddSingleton<IInstallStep>(sp => sp.GetRequiredService<WriteInstallManifestStep>());
+
+        // Stop/Start — NOT registered as IInstallStep (not part of default FreshInstall pipeline).
+        // Pulled by Update flow + Repair/Uninstall.
+        sc.AddSingleton<StopServiceStep>();
+        sc.AddSingleton<StartServiceStep>();
 
         // ViewModels
         sc.AddSingleton<WizardViewModel>();