GET and POST both call auth() first and return 401 { error:
Unauthorized } when there is no session, before doing any
validation or DB work. This is the API-side half of route-gating -
middleware.ts handles page routes but deliberately excludes /api,
so API routes verify the session themselves.
Flat permission model only (per CLAUDE.md): this checks logged-in
or not, nothing more granular. No role/permission logic added.
toanhoang