Proteus Digital Health Inc., which once promised a medical revolution with "smart pills" to track patients' adherence to drug prescriptions with just $9.5 million in cash and equivalents on its books now, filed late Monday for Chapter 11 bankruptcy protection. The privately held, 18-year-old company laid off or furloughed nearly 300 employees late last year at its Redwood City headquarters and Hayward production facility and in April received a $2.23 million loan from the federal government's Covid-19-related...