SPRINGFIELD — Maura Duffy spent a day in Chicago last September with her mother: A walk along Lake Michigan, shared meals, a boat tour highlighting Second City architecture. But this was no typical mother-daughter outing. It was the first time the two women had ever met. Since a handful of states, including Illinois, have unsealed birth certificates, thousands of adoptees have claimed them and learned about their beginnings. The 35-year-old Duffy, adopted at birth, is among 8,800 Illinois residents since 2010 …