feat: extract MyAgent core and web console

tests/MyAgent.Tests/Core/ArtifactJournalTests.cs

@@ -0,0 +1,22 @@
+using MyAgent.Core;
+using Xunit;
+
+namespace MyAgent.Tests.Core;
+
+public sealed class ArtifactJournalTests
+{
+    [Fact]
+    public void AppendAndRead_PreservesTypedArtifactsAndSequence()
+    {
+        var journal = new ArtifactJournal();
+
+        var first = journal.Append("text", "agent-a", "one");
+        var second = journal.Append("number", "agent-b", 2);
+
+        Assert.Equal(1, first.Sequence);
+        Assert.Equal(2, second.Sequence);
+        Assert.Equal(["one"], journal.Read<string>());
+        Assert.Equal([2], journal.Read<int>());
+        Assert.Equal(2, journal.Snapshot().Count);
+    }
+}