A federal judge tentatively approved a settlement agreement designed to ensure that residents of public housing units in Chicago know they can seek an exemption if they cannot afford the minimum rent of $75 a month.In a written order, U.S. District Judge Matthew F. Kennelly of the Northern District of Illinois concluded the proposed settlement reached in a class-action lawsuit filed against the Chicago Housing Authority by three residents meets the requirements of due process and Federal Rules of Civil Procedure 23(c)(2 …