As we flushed out in POC project, currently Hibernate hard-codes `?` as the only parameter marker for native query; but we require customized parameter marker (using {$undefined: true}) to work consistently with MQL generated via AST translation.

It has a long history and Hibernate side won't fix it soon for good reasons. We might need to figure out how to work around it. The easiest one is simply parse `?` as native query marker, as what has been done in Hibernate Reactive codebase (https://github.com/hibernate/hibernate-reactive/blob/main/hibernate-reactive-core/src/main/java/org/hibernate/reactive/pool/impl/Parameters.java).