WASHINGTON — The Supreme Court handed a surprising victory to the Obama administration and civil rights groups today when it upheld a key tool used for more than four decades to fight housing discrimination.The justices ruled 5-4 that federal housing laws prohibit seemingly neutral practices that harm minorities, even without proof of intentional discrimination.Justice Anthony M. Kennedy, often a swing vote, joined the court’s four liberal members in upholding the use of so-called “disparate impact” …