Solid breakdown. The one thing that decides whether this holds up past the first sprint is enforcement. Folder conventions and "dependency direction" rot the moment they're only in a doc. Two mechanical guards worth adding: put import 'server-only' at the top of lib/db and lib/auth files so a stray import from a client component is a build error instead of a leaked connection string, and wire up eslint no-restricted-paths (or eslint-plugin-boundaries) so "lib importing from components" fails CI rather than getting waved through in review. After that the structure mostly maintains itself.