feat(srp): add shader pass selection for scene draws

- let DrawingSettings carry an optional shaderPassName across managed and native scene draw APIs
- allow RenderObjectsRendererFeature to author explicit ForwardLit or Unlit scene draws
- exercise the new scene draw pass selection seam in the project render pipeline probe

engine/src/Scripting/Mono/MonoScriptRuntime.cpp

@@ -4592,7 +4592,8 @@ InternalCall_Rendering_ScriptableRenderContext_DrawRenderersByDesc(
     uint64_t nativeHandle,
     int32_t scenePhase,
     ManagedRendererListDescData* rendererListDescData,
-    MonoString* overrideMaterialPath) {
+    MonoString* overrideMaterialPath,
+    MonoString* shaderPassName) {
     ManagedScriptableRenderContextState* const state =
         FindManagedScriptableRenderContextState(nativeHandle);
     if (state == nullptr ||
@@ -4626,6 +4627,13 @@ InternalCall_Rendering_ScriptableRenderContext_DrawRenderersByDesc(
         }
     }
 
+    const std::string shaderPassNameUtf8 =
+        MonoStringToUtf8(shaderPassName);
+    if (!shaderPassNameUtf8.empty()) {
+        drawSettings.shaderPassName =
+            Containers::String(shaderPassNameUtf8.c_str());
+    }
+
     return state->sceneRecorder->RecordSceneDrawSettings(
                drawSettings)
         ? 1