ADR-001 — A module is a folder, not a class
A module is just a directory under app/ — no decorated class, no registration object.
Context
NestJS makes a module a decorated class with imports/providers/exports arrays. That descriptor exists to feed an IoC container. Without a container, the descriptor has no job.
Decision
A module is a directory under app/. Its public surface is whatever its index.ts re-exports; its HTTP surface is whatever routes.ts exports. No defineModule() registration object is required.
Consequences
Zero ceremony to declare a module — make a folder. The "module graph" is just the import graph. Cost: conventions (file names, the app/ root) are load-bearing; the build must know them.