Developing a Multisensor-Based Machine Learning Technology (Aidar Decompensation Index) for Real-Time Automated Detection of Post–COVID-19 Condition: Protocol for an Observational Study - Jenny Mathew; Jaclyn A Pagliaro; Sathyanarayanan Elumalai; Lauren K Wash; Ka Ly; Alison J Leibowitz; Varsha G Vimalananda (JMIR Research Protocols)