Inside, the walls are painted white and gray, institutional colors. But it’s well kept, and the grounds are pretty, the lawn is mowed, and flowers are planted. That’s because work crews — a.k.a. prisoners, a.k.a. Chani Schwarcz’s clients — maintain the gardens and the building. Chani Schwarcz, LMSW, works as a social worker/discharger planner in Rikers Island.