New member onboarding text series over the first two weeks

Set up a short series of texts for new members: one the day after joining with a link to the app and schedule, one after one week asking if they've found a class they like, and one after two weeks inviting them to a free session with a trainer to check their form.

Why it works: New members who feel checked on during the first two weeks are less likely to quietly stop coming without ever using the membership.