The House gave final approval Thursday to legislation protecting same-sex marriages, a monumental step in a decadeslong battle for nationwide recognition of such unions that reflects a stunning turnaround in societal attitudes.President Joe Biden is expected to promptly sign the measure, which requires all states to recognize same-sex marriages, a relief for hundreds of thousands of couples who have married since the Supreme Court’s 2015 decision that legalized those marriages nationwide.The bipartisan legislation …