Create queued reminder texts from emailed CSV attachments

Emailed CSVs with guest bookings force manual copying and delay reminder texts. Get texts queued automatically so coordinators have messages ready by noon one week before sessions.

Overview

Stop copying rows from emailed CSVs and eliminate last-minute reminder prep; queue texts directly from the attachment so reservation coordinators don't scramble. Messages will be ready and queued by noon one week before each session, reducing manual work and missed notices.