Refactor code structure and optimize performance across multiple modules

src/Scanner/__Tests/StellaOps.Scanner.Cache.Tests/LayerCacheRoundTripTests.cs

@@ -42,7 +42,8 @@ public sealed class LayerCacheRoundTripTests : IAsyncLifetime
         _fileCas = new FileContentAddressableStore(_options, NullLogger<FileContentAddressableStore>.Instance, _timeProvider);
     }
 
-    [Fact]
+    [Trait("Category", TestCategories.Unit)]
+        [Fact]
     public async Task RoundTrip_Succeeds_And_Respects_Ttl_And_ImportExport()
     {
         var layerDigest = "sha256:abcd1234";
@@ -109,6 +110,7 @@ public sealed class LayerCacheRoundTripTests : IAsyncLifetime
         // Compaction removes CAS entry once over threshold.
         // Force compaction by writing a large entry.
         using var largeStream = CreateStream(new string('x', 400_000));
+using StellaOps.TestKit;
         var largeHash = "sha256:" + new string('e', 64);
         await _fileCas.PutAsync(new FileCasPutRequest(largeHash, largeStream), CancellationToken.None);
         _timeProvider.Advance(TimeSpan.FromMinutes(1));