Build a group coaching platform

Task: Build a group coaching and cohort management platform called "Cohort OS", for running structured group programs. Context: The platform is for coaches who run paid group programs and their participants, and the design is coach-first. It is built with React and Supabase, uses Stripe Connect for coach payouts and Resend for session reminders and feedback prompts. In the program builder the coach sets the program name, session count, cadence (weekly or bi-weekly), maximum participants, price and start date, and each session has a title, a pre-work assignment and a post-session reflection prompt. The participant portal is one dashboard with the program timeline, upcoming sessions, submitted assignments and peer reflections. Participants submit written or link-based assignments before each session, and the coach sees all submissions in one view and leaves written feedback per submission. After each session each participant gives one piece of structured feedback to one other participant, rotating automatically so everyone gives and receives equally. The progress tracker is a coach dashboard with the assignment completion rate per participant, attendance and a simple engagement score. At program completion an automatic PDF certificate carries the participant name, program name, coach name and completion date. Rules: - Use a clean, professional design. - Build in stages that each run on their own: program builder and participant portal first, then assignments and feedback rounds, then payments, tracking and certificates. Result: The database schema, the file structure, the key code per feature, then 3 lines on how to run it.