Refactor sprint 34 validation helpers for architecture compliance

editor/src/ValidationErrorUtil.h

@@ -0,0 +1,9 @@
+#pragma once
+
+#include <string>
+
+inline bool failWith(std::string* error, const char* code) {
+    if (!error) return false;
+    *error = code;
+    return false;
+}