feat(srp): add descriptor-driven object draw authoring

- bridge renderer list descriptors into ScriptableRenderContext scene draw calls
- reuse DrawObjectsPass across Universal and project custom renderers
- add RenderObjectsRendererFeature for package-level object draw extension

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

@@ -67,12 +67,22 @@ namespace XCEngine.Rendering
         public bool DrawRenderers(
             SceneRenderPhase scenePhase,
             RendererListType rendererListType)
+        {
+            return DrawRenderers(
+                scenePhase,
+                RendererListDesc.CreateDefault(
+                    rendererListType));
+        }
+
+        public bool DrawRenderers(
+            SceneRenderPhase scenePhase,
+            RendererListDesc rendererListDesc)
         {
             return InternalCalls
-                .Rendering_ScriptableRenderContext_DrawRenderers(
+                .Rendering_ScriptableRenderContext_DrawRenderersByDesc(
                     m_nativeHandle,
                     (int)scenePhase,
-                    (int)rendererListType);
+                    ref rendererListDesc);
         }
 
         public bool RecordOpaqueScenePhase()
@@ -133,14 +143,16 @@ namespace XCEngine.Rendering
         {
             return DrawRenderers(
                 SceneRenderPhase.Opaque,
-                RendererListType.Opaque);
+                RendererListDesc.CreateDefault(
+                    RendererListType.Opaque));
         }
 
         public bool DrawTransparentRenderers()
         {
             return DrawRenderers(
                 SceneRenderPhase.Transparent,
-                RendererListType.Transparent);
+                RendererListDesc.CreateDefault(
+                    RendererListType.Transparent));
         }
 
         public RenderGraphTextureHandle CreateTransientTexture(