Refactor code structure and optimize performance across multiple modules

src/Signals/__Tests/StellaOps.Signals.Tests/SimpleJsonCallgraphParserGateTests.cs

@@ -11,7 +11,8 @@ namespace StellaOps.Signals.Tests;
 
 public sealed class SimpleJsonCallgraphParserGateTests
 {
-    [Fact]
+    [Trait("Category", TestCategories.Unit)]
+        [Fact]
     public async Task ParseAsync_parses_gate_fields_on_edges()
     {
         var json = """
@@ -45,6 +46,7 @@ public sealed class SimpleJsonCallgraphParserGateTests
 
         var parser = new SimpleJsonCallgraphParser("csharp");
         await using var stream = new MemoryStream(Encoding.UTF8.GetBytes(json), writable: false);
+using StellaOps.TestKit;
         var parsed = await parser.ParseAsync(stream, CancellationToken.None);
 
         parsed.Edges.Should().ContainSingle();