feat(worker): add AgentFileService for filesystem agent management

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/ClaudeDo.Worker.Tests/Services/AgentFileServiceTests.cs

@@ -0,0 +1,84 @@
+using ClaudeDo.Worker.Services;
+
+namespace ClaudeDo.Worker.Tests.Services;
+
+public sealed class AgentFileServiceTests : IDisposable
+{
+    private readonly string _agentDir;
+    private readonly AgentFileService _service;
+
+    public AgentFileServiceTests()
+    {
+        _agentDir = Path.Combine(Path.GetTempPath(), $"claudedo_agents_test_{Guid.NewGuid():N}");
+        Directory.CreateDirectory(_agentDir);
+        _service = new AgentFileService(_agentDir);
+    }
+
+    [Fact]
+    public async Task Scan_Returns_Empty_For_Empty_Directory()
+    {
+        var agents = await _service.ScanAsync();
+        Assert.Empty(agents);
+    }
+
+    [Fact]
+    public async Task Scan_Parses_Frontmatter()
+    {
+        var content = "---\nname: Test Agent\ndescription: A test agent for unit tests\n---\n\nYou are a test agent.";
+        await File.WriteAllTextAsync(Path.Combine(_agentDir, "test.md"), content);
+
+        var agents = await _service.ScanAsync();
+        Assert.Single(agents);
+        Assert.Equal("Test Agent", agents[0].Name);
+        Assert.Equal("A test agent for unit tests", agents[0].Description);
+        Assert.EndsWith("test.md", agents[0].Path);
+    }
+
+    [Fact]
+    public async Task Scan_Uses_Filename_When_No_Frontmatter()
+    {
+        await File.WriteAllTextAsync(Path.Combine(_agentDir, "simple.md"), "Just instructions.");
+
+        var agents = await _service.ScanAsync();
+        Assert.Single(agents);
+        Assert.Equal("simple", agents[0].Name);
+        Assert.Equal("", agents[0].Description);
+    }
+
+    [Fact]
+    public async Task Write_And_Read_Roundtrips()
+    {
+        var path = Path.Combine(_agentDir, "new-agent.md");
+        var content = "---\nname: New\ndescription: Desc\n---\nBody";
+        await _service.WriteAsync(path, content);
+
+        var read = await _service.ReadAsync(path);
+        Assert.Equal(content, read);
+    }
+
+    [Fact]
+    public async Task Delete_Removes_File()
+    {
+        var path = Path.Combine(_agentDir, "to-delete.md");
+        await File.WriteAllTextAsync(path, "temp");
+
+        await _service.DeleteAsync(path);
+        Assert.False(File.Exists(path));
+    }
+
+    [Fact]
+    public async Task Scan_Ignores_Non_Md_Files()
+    {
+        await File.WriteAllTextAsync(Path.Combine(_agentDir, "notes.txt"), "not an agent");
+        await File.WriteAllTextAsync(Path.Combine(_agentDir, "agent.md"), "---\nname: Real\ndescription: Yes\n---\nBody");
+
+        var agents = await _service.ScanAsync();
+        Assert.Single(agents);
+        Assert.Equal("Real", agents[0].Name);
+    }
+
+    public void Dispose()
+    {
+        try { Directory.Delete(_agentDir, true); } catch { }
+    }
+}