Can the Michigan Attorney General prosecute Ford for hosting the President, while the factory is under a DPA contract?

McCulloch v. Maryland, always and forever.

Today, President Trump visited the Ford factory in Ypsilanti, Michigan. Under state law, everyone in the factory was required to wear a mask. President Trump refused to wear a mask. The Michigan Attorney General said she would investigate Ford for letting the President visit the plant without a mask.

This Ford Factory is currently providing services under a Defense Production Act contract. Is the company a federal agent for purposes of the DPA? If so, are there any Supremacy Clause issues with prosecuting Ford for the President's behavior? Is this case like McCulloch v. Maryland, where the state of Maryland disciplined a federal bank employee?

We are living in a real-time final exam hypothetical.