Paul Neel, a professor at Cal Poly San Luis Obispo, has been appointed state architect by Gov. George Deukmejian. If confirmed by the Senate, Neel would succeed Michael Bocchicchio, who resigned Nov. 15. The state architect is in charge of erecting state buildings. Neel, 56, has operated his own architectural firm since 1963, one year after he became professor of architecture at Cal Poly. Neel, a Republican, would serve until Jan. 15, 1991.