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/Universal/UniversalRenderPipelineAsset.cs

@@ -41,6 +41,11 @@ namespace XCEngine.Rendering.Universal
                 : string.Empty;
         }
 
+        protected override void ReleaseRuntimeResources()
+        {
+            ReleaseRendererDataRuntimeResources();
+        }
+
         internal ScriptableRendererData GetDefaultRendererData()
         {
             return GetRendererData(defaultRendererIndex);
@@ -92,6 +97,42 @@ namespace XCEngine.Rendering.Universal
             defaultRendererIndex = 0;
         }
 
+        protected void ReleaseRendererDataRuntimeResources()
+        {
+            EnsureRendererDataList();
+
+            for (int i = 0; i < rendererDataList.Length; ++i)
+            {
+                ScriptableRendererData rendererData =
+                    rendererDataList[i];
+                if (rendererData == null ||
+                    WasRendererDataReleasedEarlier(i))
+                {
+                    continue;
+                }
+
+                rendererData.ReleaseRuntimeResourcesInstance();
+            }
+        }
+
+        private bool WasRendererDataReleasedEarlier(
+            int rendererDataIndex)
+        {
+            ScriptableRendererData rendererData =
+                rendererDataList[rendererDataIndex];
+            for (int i = 0; i < rendererDataIndex; ++i)
+            {
+                if (object.ReferenceEquals(
+                        rendererDataList[i],
+                        rendererData))
+                {
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
         private int ResolveRendererIndex(
             int rendererIndex)
         {