A federal judge overseeing New York City’s Rikers Island jail complex on Wednesday found the city in contempt for failing to stem violence and excessive force at the facility, and said she was leaning toward taking control of the city’s jails. The judge, Laura Taylor Swain, said in a 65-page opinion that the city and its Department of Correction had violated the constitutional rights of prisoners and staff members alike by exposing them to danger, and had intentionally ignored her orders.