feat(ui): add InstallerLocator

tests/ClaudeDo.Ui.Tests/Services/InstallerLocatorTests.cs

@@ -0,0 +1,58 @@
+using ClaudeDo.Ui.Services;
+
+namespace ClaudeDo.Ui.Tests.Services;
+
+public class InstallerLocatorTests : IDisposable
+{
+    private readonly string _root;
+
+    public InstallerLocatorTests()
+    {
+        _root = Path.Combine(Path.GetTempPath(), "ClaudeDo.Ui.Tests-" + Guid.NewGuid().ToString("N"));
+        Directory.CreateDirectory(_root);
+    }
+
+    public void Dispose() { try { Directory.Delete(_root, true); } catch { } }
+
+    [Fact]
+    public void Find_WalkUpFromAppDir_ToInstallJsonSibling()
+    {
+        var installDir = Path.Combine(_root, "ClaudeDo");
+        var appDir = Path.Combine(installDir, "app");
+        var uninstallerDir = Path.Combine(installDir, "uninstaller");
+        Directory.CreateDirectory(appDir);
+        Directory.CreateDirectory(uninstallerDir);
+
+        File.WriteAllText(Path.Combine(installDir, "install.json"), "{}");
+        var installerPath = Path.Combine(uninstallerDir, "ClaudeDo.Installer.exe");
+        File.WriteAllText(installerPath, "x");
+
+        var locator = new InstallerLocator();
+        var found = locator.FindByWalkingUp(appDir);
+
+        Assert.Equal(installerPath, found);
+    }
+
+    [Fact]
+    public void Find_ReturnsNullWhenNoInstallJson()
+    {
+        var appDir = Path.Combine(_root, "somewhere", "app");
+        Directory.CreateDirectory(appDir);
+
+        var locator = new InstallerLocator();
+        Assert.Null(locator.FindByWalkingUp(appDir));
+    }
+
+    [Fact]
+    public void Find_ReturnsNullWhenInstallerMissingFromUninstallerDir()
+    {
+        var installDir = Path.Combine(_root, "ClaudeDo");
+        var appDir = Path.Combine(installDir, "app");
+        Directory.CreateDirectory(appDir);
+        Directory.CreateDirectory(Path.Combine(installDir, "uninstaller"));
+        File.WriteAllText(Path.Combine(installDir, "install.json"), "{}");
+
+        var locator = new InstallerLocator();
+        Assert.Null(locator.FindByWalkingUp(appDir));
+    }
+}