SAN ANTONIO (AP) — Sandra Mosqueda watched with an amused smile as her 2-year-old son, Atreus, began sweeping the floor with a miniature mop. Atreus is part of the inaugural class of infants and toddlers receiving free preschool in a citywide program in San Antonio, Texas . It’s something his mother doesn’t take for granted. As a child, she herself wasn’t able to start preschool this young. In the case of her two older boys — now in first grade and kindergarten — the free preschool set them up