feat(installer): replace sync ModeDetector with async InstallModeDetector

Placeholder edit to App.xaml.cs to keep the project building until Task 11
wires the new async detector.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/ClaudeDo.Installer/App.xaml.cs

@@ -19,20 +19,12 @@ public partial class App : Application
     {
         base.OnStartup(e);
 
-        var mode = ModeDetector.Detect();
         _services = BuildServices();
 
-        Window mainWindow = mode switch
+        // TODO(Task 11): replace with async InstallModeDetector
+        Window mainWindow = new WizardWindow
         {
-            InstallerMode.Wizard => new WizardWindow
-            {
-                DataContext = _services.GetRequiredService<WizardViewModel>()
-            },
-            InstallerMode.Settings => new SettingsWindow
-            {
-                DataContext = _services.GetRequiredService<SettingsViewModel>()
-            },
-            _ => throw new InvalidOperationException($"Unknown installer mode: {mode}")
+            DataContext = _services.GetRequiredService<WizardViewModel>()
         };
 
         DarkTitleBar.Apply(mainWindow);

src/ClaudeDo.Installer/Core/InstallModeDetector.cs

@@ -0,0 +1,41 @@
+namespace ClaudeDo.Installer.Core;
+
+public sealed record DetectedState(
+    InstallerMode Mode,
+    InstallManifest? Existing,
+    GiteaRelease? LatestRelease,
+    string? LatestVersion);
+
+public sealed class InstallModeDetector
+{
+    private readonly IReleaseClient _releases;
+
+    public InstallModeDetector(IReleaseClient releases)
+    {
+        _releases = releases;
+    }
+
+    public async Task<DetectedState> DetectAsync(string installDir, CancellationToken ct)
+    {
+        var manifest = InstallManifestStore.TryRead(installDir);
+        if (manifest is null)
+            return new DetectedState(InstallerMode.FreshInstall, null, null, null);
+
+        var release = await _releases.GetLatestReleaseAsync(ct);
+        if (release is null)
+            return new DetectedState(InstallerMode.Config, manifest, null, null);
+
+        var latestVersion = release.TagName.TrimStart('v', 'V');
+        if (IsNewer(latestVersion, manifest.Version))
+            return new DetectedState(InstallerMode.Update, manifest, release, latestVersion);
+
+        return new DetectedState(InstallerMode.Config, manifest, release, latestVersion);
+    }
+
+    private static bool IsNewer(string latest, string current)
+    {
+        if (!Version.TryParse(latest, out var lv)) return false;
+        if (!Version.TryParse(current, out var cv)) return false;
+        return lv > cv;
+    }
+}

src/ClaudeDo.Installer/Core/InstallerMode.cs

@@ -1,19 +1,8 @@
-using System.IO;
-using ClaudeDo.Data;
-
 namespace ClaudeDo.Installer.Core;
 
-public enum InstallerMode { Wizard, Settings }
-
-public static class ModeDetector
+public enum InstallerMode
 {
-    public static InstallerMode Detect()
-    {
-        var root = Paths.AppDataRoot();
-        var workerConfig = Path.Combine(root, "worker.config.json");
-        var uiConfig = Path.Combine(root, "ui.config.json");
-        return File.Exists(workerConfig) && File.Exists(uiConfig)
-            ? InstallerMode.Settings
-            : InstallerMode.Wizard;
-    }
+    FreshInstall,   // No install.json present -> run full wizard
+    Update,         // install.json present, newer release available
+    Config,         // install.json present, no update (or API unreachable)
 }

tests/ClaudeDo.Installer.Tests/InstallModeDetectorTests.cs

@@ -0,0 +1,105 @@
+using ClaudeDo.Installer.Core;
+
+namespace ClaudeDo.Installer.Tests;
+
+public sealed class InstallModeDetectorTests : IDisposable
+{
+    private readonly string _tempDir;
+
+    public InstallModeDetectorTests()
+    {
+        _tempDir = Path.Combine(Path.GetTempPath(), "ClaudeDoDetector-" + Guid.NewGuid().ToString("N"));
+        Directory.CreateDirectory(_tempDir);
+    }
+
+    public void Dispose()
+    {
+        try { Directory.Delete(_tempDir, recursive: true); } catch { }
+    }
+
+    private sealed class FakeReleaseClient : IReleaseClient
+    {
+        public GiteaRelease? Release { get; set; }
+        public Task<GiteaRelease?> GetLatestReleaseAsync(CancellationToken ct) => Task.FromResult(Release);
+        public Task DownloadAsync(string url, string destPath, IProgress<long> progress, CancellationToken ct)
+            => throw new NotSupportedException();
+    }
+
+    [Fact]
+    public async Task Detect_FreshInstall_WhenManifestMissing()
+    {
+        var detector = new InstallModeDetector(new FakeReleaseClient());
+
+        var state = await detector.DetectAsync(_tempDir, CancellationToken.None);
+
+        Assert.Equal(InstallerMode.FreshInstall, state.Mode);
+        Assert.Null(state.Existing);
+    }
+
+    [Fact]
+    public async Task Detect_Config_WhenManifestPresent_And_Api_Unreachable()
+    {
+        InstallManifestStore.Write(_tempDir,
+            new InstallManifest("0.1.0", _tempDir, _tempDir, DateTimeOffset.UtcNow));
+
+        var detector = new InstallModeDetector(new FakeReleaseClient { Release = null });
+
+        var state = await detector.DetectAsync(_tempDir, CancellationToken.None);
+
+        Assert.Equal(InstallerMode.Config, state.Mode);
+        Assert.Equal("0.1.0", state.Existing!.Version);
+    }
+
+    [Fact]
+    public async Task Detect_Update_WhenLatest_GreaterThan_Installed()
+    {
+        InstallManifestStore.Write(_tempDir,
+            new InstallManifest("0.1.0", _tempDir, _tempDir, DateTimeOffset.UtcNow));
+
+        var fake = new FakeReleaseClient
+        {
+            Release = new GiteaRelease("v0.2.0", "v0.2.0", Array.Empty<ReleaseAsset>())
+        };
+        var detector = new InstallModeDetector(fake);
+
+        var state = await detector.DetectAsync(_tempDir, CancellationToken.None);
+
+        Assert.Equal(InstallerMode.Update, state.Mode);
+        Assert.Equal("0.1.0", state.Existing!.Version);
+        Assert.Equal("0.2.0", state.LatestVersion);
+    }
+
+    [Fact]
+    public async Task Detect_Config_WhenLatest_EqualsOrOlderThan_Installed()
+    {
+        InstallManifestStore.Write(_tempDir,
+            new InstallManifest("0.2.0", _tempDir, _tempDir, DateTimeOffset.UtcNow));
+
+        var fake = new FakeReleaseClient
+        {
+            Release = new GiteaRelease("v0.2.0", "v0.2.0", Array.Empty<ReleaseAsset>())
+        };
+        var detector = new InstallModeDetector(fake);
+
+        var state = await detector.DetectAsync(_tempDir, CancellationToken.None);
+
+        Assert.Equal(InstallerMode.Config, state.Mode);
+    }
+
+    [Fact]
+    public async Task Detect_Config_WhenInstalledIs_Newer_Than_Latest()
+    {
+        InstallManifestStore.Write(_tempDir,
+            new InstallManifest("0.3.0", _tempDir, _tempDir, DateTimeOffset.UtcNow));
+
+        var fake = new FakeReleaseClient
+        {
+            Release = new GiteaRelease("v0.2.0", "v0.2.0", Array.Empty<ReleaseAsset>())
+        };
+        var detector = new InstallModeDetector(fake);
+
+        var state = await detector.DetectAsync(_tempDir, CancellationToken.None);
+
+        Assert.Equal(InstallerMode.Config, state.Mode);
+    }
+}