feat(releases): add SelfUpdater installer-asset matching

tests/ClaudeDo.Releases.Tests/SelfUpdaterTests.cs

@@ -0,0 +1,44 @@
+namespace ClaudeDo.Releases.Tests;
+
+public class SelfUpdaterAssetMatchingTests
+{
+    [Fact]
+    public void FindInstallerAsset_PicksInstallerExeByPattern()
+    {
+        var assets = new[]
+        {
+            new ReleaseAsset("ClaudeDo-0.3.0-win-x64.zip", "https://x/app.zip", 10),
+            new ReleaseAsset("ClaudeDo.Installer-0.3.0.exe", "https://x/inst.exe", 20),
+            new ReleaseAsset("checksums.txt", "https://x/checks", 1),
+        };
+
+        var result = SelfUpdater.FindInstallerAsset(assets);
+
+        Assert.NotNull(result);
+        Assert.Equal("ClaudeDo.Installer-0.3.0.exe", result!.Asset.Name);
+        Assert.Equal("0.3.0", result.Version);
+    }
+
+    [Fact]
+    public void FindInstallerAsset_ReturnsNullWhenAbsent()
+    {
+        var assets = new[]
+        {
+            new ReleaseAsset("ClaudeDo-0.3.0-win-x64.zip", "https://x/app.zip", 10),
+        };
+
+        Assert.Null(SelfUpdater.FindInstallerAsset(assets));
+    }
+
+    [Fact]
+    public void FindInstallerAsset_IgnoresAppZipThatContainsInstaller()
+    {
+        var assets = new[]
+        {
+            new ReleaseAsset("ClaudeDo.Installer.Portable-0.3.0.zip", "https://x/1", 1),
+            new ReleaseAsset("not-the-installer.exe", "https://x/2", 1),
+        };
+
+        Assert.Null(SelfUpdater.FindInstallerAsset(assets));
+    }
+}