Refactor code structure and optimize performance across multiple modules

src/__Tests/Provenance/StellaOps.Provenance.Attestation.Tests/VerificationLibraryTests.cs

@@ -6,7 +6,8 @@ namespace StellaOps.Provenance.Attestation.Tests;
 
 public sealed class VerificationLibraryTests
 {
-    [Fact]
+    [Trait("Category", TestCategories.Unit)]
+        [Fact]
     public async Task HmacVerifier_FailsWhenKeyExpired()
     {
         var key = new InMemoryKeyProvider("k1", Encoding.UTF8.GetBytes("secret"), DateTimeOffset.UtcNow.AddMinutes(-1));
@@ -22,7 +23,8 @@ public sealed class VerificationLibraryTests
         Assert.Contains("time", result.Reason);
     }
 
-    [Fact]
+    [Trait("Category", TestCategories.Unit)]
+        [Fact]
     public async Task HmacVerifier_FailsWhenClockSkewTooLarge()
     {
         var now = new DateTimeOffset(2025, 11, 22, 12, 0, 0, TimeSpan.Zero);
@@ -37,7 +39,8 @@ public sealed class VerificationLibraryTests
         Assert.False(result.IsValid);
     }
 
-    [Fact]
+    [Trait("Category", TestCategories.Unit)]
+        [Fact]
     public void MerkleRootVerifier_DetectsMismatch()
     {
         var leaves = new[]
@@ -54,7 +57,8 @@ public sealed class VerificationLibraryTests
         Assert.Equal("merkle root mismatch", result.Reason);
     }
 
-    [Fact]
+    [Trait("Category", TestCategories.Unit)]
+        [Fact]
     public void ChainOfCustodyVerifier_ComputesAggregate()
     {
         var hops = new[]
@@ -64,6 +68,7 @@ public sealed class VerificationLibraryTests
         };
 
         using var sha = System.Security.Cryptography.SHA256.Create();
+using StellaOps.TestKit;
         var aggregate = sha.ComputeHash(Array.Empty<byte>().Concat(hops[0]).ToArray());
         aggregate = sha.ComputeHash(aggregate.Concat(hops[1]).ToArray());