A federal judge has sunk the hopes of a boat manufacturer trying to undo a $25 million settlement agreement it entered just minutes before a Cook County jury returned a verdict in its favor.In a written opinion Tuesday, U.S. District Judge Manish S. Shah threw out a lawsuit accusing a former Cook County court clerk of conspiring with opposing counsel in a product-liability case to deny Brunswick Corp. its right to due process.Brunswick argued that, while trying to wrap up settlement negotiations between the two sides, then …