Shawnika Howell has been a nurse for 13 years, primarily in long-term care, but around the time of the winter 2021 COVID-19 surge, she decided to find some extra work through something new: an app called Clipboard. The app lets nurses and nurse aides book individual shifts for a set number of hours with health care facilities, get paid, and move on to the next gig. Essentially, it’s Uber for...