partly or unimplemented features - now implemented

src/BinaryIndex/__Libraries/StellaOps.BinaryIndex.GoldenSet/Extensions/GoldenSetServiceCollectionExtensions.cs

@@ -35,6 +35,9 @@ public static class GoldenSetServiceCollectionExtensions
         services.TryAddSingleton<ISinkRegistry, SinkRegistry>();
         services.TryAddSingleton<IGoldenSetValidator, GoldenSetValidator>();
 
+        // Cross-distro coverage matrix for backport validation
+        services.TryAddSingleton<ICrossDistroCoverageService, CrossDistroCoverageService>();
+
         // Memory cache (if not already registered)
         services.AddMemoryCache();