Testing a Machine Learning–Based Adaptive Motivational System for Socioeconomically Disadvantaged Smokers (Adapt2Quit): Protocol for a Randomized Controlled Trial - Ariana Kamberi; Benjamin Weitz; Julie Flahive; Julianna Eve; Reem Najjar; Tara Liaghat; Daniel Ford; Peter Lindenauer; Sharina Person; Thomas K Houston; Megan E Gauvey-Kern; Jackie Lobien; et al. (JMIR Research Protocols)