architecture

• One question per diagram: who uses it, how the website is built, what the server does, what it relies on.
• The server diagram shows the repo clones beside Postgres because lesson content is never stored in the database (course-as-code).
• The Postgres host is drawn as "Supabase or Neon": the runbooks name both and the repo does not say which holds production.
• A month costs $0–20: Vercel Hobby is free and Pro is $20 a seat; Postgres, SES and the GitHub and Google sign-ins sit on free tiers. Function time, database size and email grow with students.
• The diagrams are generated: edit the .json in architecture/, then run archify finalize architecture <name>.json <name>.html --quality showcase there. Never hand-edit the .html.
• Architecture is canon's, not the design set's. Why each part of the stack was chosen is in CLAUDE.md and hosting.