feat(worker): session skill registry (install/update/remove, pinned clone)

tests/ClaudeDo.Worker.Tests/Skills/FakeRepoCloner.cs

@@ -0,0 +1,43 @@
+using ClaudeDo.Worker.Skills;
+
+namespace ClaudeDo.Worker.Tests.Skills;
+
+/// <summary>
+/// Test double for IRepoCloner: "clones" by copying a pre-built local fixture directory,
+/// so tests never touch the network or invoke real git. One fixture dir + pinned ref can
+/// be registered per source URL.
+/// </summary>
+public sealed class FakeRepoCloner : IRepoCloner
+{
+    private readonly Dictionary<string, (string FixtureDir, string PinnedRef)> _sources = new();
+    private int _cloneCount;
+
+    public int CloneCount => _cloneCount;
+
+    public void Register(string url, string fixtureDir, string pinnedRef) =>
+        _sources[url] = (fixtureDir, pinnedRef);
+
+    public Task<ClonedRepo> CloneAsync(string url, string destDir, CancellationToken ct)
+    {
+        _cloneCount++;
+        if (!_sources.TryGetValue(url, out var source))
+            throw new InvalidOperationException($"FakeRepoCloner has no fixture registered for '{url}'.");
+
+        CopyDirectory(source.FixtureDir, destDir);
+        return Task.FromResult(new ClonedRepo(destDir, source.PinnedRef));
+    }
+
+    private static void CopyDirectory(string sourceDir, string destDir)
+    {
+        Directory.CreateDirectory(destDir);
+        foreach (var file in Directory.EnumerateFiles(sourceDir, "*", SearchOption.AllDirectories))
+        {
+            var relative = Path.GetRelativePath(sourceDir, file);
+            var destPath = Path.Combine(destDir, relative);
+            var destParent = Path.GetDirectoryName(destPath);
+            if (!string.IsNullOrEmpty(destParent))
+                Directory.CreateDirectory(destParent);
+            File.Copy(file, destPath, overwrite: true);
+        }
+    }
+}