feat(ui): add InstallerLocator

src/ClaudeDo.Ui/ClaudeDo.Ui.csproj

@@ -10,6 +10,7 @@
     <PackageReference Include="CommunityToolkit.Mvvm" Version="8.4.1" />
     <PackageReference Include="Microsoft.AspNetCore.SignalR.Client" Version="8.0.11" />
     <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="8.0.1" />
+    <PackageReference Include="Microsoft.Win32.Registry" Version="5.0.0" />
   </ItemGroup>
 
   <PropertyGroup>

src/ClaudeDo.Ui/Services/InstallerLocator.cs

@@ -0,0 +1,47 @@
+namespace ClaudeDo.Ui.Services;
+
+public sealed class InstallerLocator
+{
+    private const string InstallJson = "install.json";
+    private const string InstallerExe = "ClaudeDo.Installer.exe";
+    private const string UninstallerSubdir = "uninstaller";
+
+    public string? Find()
+        => FindByWalkingUp(AppContext.BaseDirectory) ?? FindByRegistry();
+
+    public string? FindByWalkingUp(string startDir)
+    {
+        var dir = new DirectoryInfo(startDir);
+        while (dir is not null)
+        {
+            var manifest = Path.Combine(dir.FullName, InstallJson);
+            if (File.Exists(manifest))
+            {
+                var candidate = Path.Combine(dir.FullName, UninstallerSubdir, InstallerExe);
+                return File.Exists(candidate) ? candidate : null;
+            }
+            dir = dir.Parent;
+        }
+        return null;
+    }
+
+    [System.Runtime.Versioning.SupportedOSPlatform("windows")]
+    public string? FindByRegistry()
+    {
+        if (!OperatingSystem.IsWindows()) return null;
+
+        try
+        {
+            using var key = Microsoft.Win32.Registry.LocalMachine
+                .OpenSubKey(@"Software\Microsoft\Windows\CurrentVersion\Uninstall\ClaudeDo");
+            var location = key?.GetValue("InstallLocation") as string;
+            if (string.IsNullOrEmpty(location)) return null;
+            var candidate = Path.Combine(location, UninstallerSubdir, InstallerExe);
+            return File.Exists(candidate) ? candidate : null;
+        }
+        catch
+        {
+            return null;
+        }
+    }
+}