refactor(srp): add managed lifecycle cleanup seams

Invoke managed pipeline disposal and asset runtime cleanup from the native bridge lifecycle. Add Universal renderer and feature cleanup hooks plus regression probes to verify runtime cache teardown semantics.

managed/XCEngine.ScriptCore/Rendering/Core/ScriptableRenderPipelineAsset.cs

@@ -8,6 +8,11 @@ namespace XCEngine.Rendering
         {
         }
 
+        internal void ReleaseRuntimeResourcesInstance()
+        {
+            ReleaseRuntimeResources();
+        }
+
         protected virtual ScriptableRenderPipeline CreatePipeline()
         {
             return null;
@@ -27,6 +32,10 @@ namespace XCEngine.Rendering
         {
             return string.Empty;
         }
+
+        protected virtual void ReleaseRuntimeResources()
+        {
+        }
     }
 }