PHILADELPHIA — The invitations were written in Dari, Pashto, and English. The food included traditional Afghan fare, platters of dried fruits, and cups of hot tea. The babies were, well, adorable. By turn they cried out loud or slept in silence, as around them balloons popped and plates spilled and older siblings laughed and chased across a brightly decorated conference room on the second floor of a Center City hotel. That’s where newly arrived Afghan mothers and mothers-to-be were welcomed to an old American tradition — a baby shower, and a big one, thrown last week by Nationalities Service C…