In a blow to government efforts to combat money laundering, a federal court has ruled that the Treasury Department cannot require some small businesses to report personal details about their owners.Under a section of a 2020 law that took effect Jan. 1, small businesses must share details about their so-called beneficial owners, individuals who hold financial stakes in a company or have significant power over their business decisions. The law, the Corporate Transparency Act, passed with bipartisan support in Congress and was intended to help the Treasury Department’s financial-crimes…