NEW YORK — Selene Sanchez wakes up early in the morning and kisses her 2-year-old son before dashing off to cleaning jobs across the city. She travels to different houses, scrubbing floors and tidying up before heading home, to the emergency shelter where she lives. Sanchez, 30, makes it back by lunchtime, when she and her husband switch places. Then he goes off to work, while she stays with Beymar, their son. Later in the day she heads out again to search for more work. Sometimes she gets lucky — a new job comes up, and she can work an hour or two, bringing home a few more dollars. The massiv...