feat(worker): resolve and seed session skills before each run

tests/ClaudeDo.Worker.Tests/Infrastructure/FakeSessionSkillSeeder.cs

@@ -0,0 +1,18 @@
+using System.Collections.Concurrent;
+using ClaudeDo.Worker.Skills;
+
+namespace ClaudeDo.Worker.Tests.Infrastructure;
+
+public sealed class FakeSessionSkillSeeder : ISessionSkillSeeder
+{
+    public int CallCount;
+    public readonly record struct Call(string WorkingDir, IReadOnlyList<string> SkillNames, bool IsWorktree);
+    public readonly ConcurrentQueue<Call> Calls = new();
+
+    public Task SeedAsync(string workingDir, IReadOnlyList<string> skillNames, bool isWorktree, CancellationToken ct)
+    {
+        Interlocked.Increment(ref CallCount);
+        Calls.Enqueue(new Call(workingDir, skillNames, isWorktree));
+        return Task.CompletedTask;
+    }
+}