Add desktop discovery responder

WirelessTextSyncer.Windows.Tests/SyncMessageTests.cs

@@ -59,6 +59,21 @@ public sealed class SyncMessageTests
             keyboard.Calls);
     }
 
+    [TestMethod]
+    public void DiscoveryResponseContainsServiceEndpoint()
+    {
+        using var discovery = new DiscoveryResponderService(() => "192.168.1.10", () => 8181, "Desktop-WIN11");
+
+        using var document = JsonDocument.Parse(discovery.BuildResponseJson());
+        var root = document.RootElement;
+
+        Assert.AreEqual("wirelessTextSyncer.service", root.GetProperty("type").GetString());
+        Assert.AreEqual(1, root.GetProperty("version").GetInt32());
+        Assert.AreEqual("Desktop-WIN11", root.GetProperty("name").GetString());
+        Assert.AreEqual("192.168.1.10", root.GetProperty("host").GetString());
+        Assert.AreEqual(8181, root.GetProperty("port").GetInt32());
+    }
+
     private sealed class RecordingKeyboardInjectionService : IKeyboardInjectionService
     {
         public List<string> Calls { get; } = [];