Define strategy for sharing TypeScript types across frontend and backend #16
Description
Frontend and backend currently live in separate subprojects, but some types
(API payloads, validation schemas, shared contracts) need to be shared.
This issue tracks:
- How cross-subproject TypeScript types should be defined and owned
- Whether shared types live in a dedicated package or are generated
- Direction of dependencies (backend → shared → frontend, etc.)
- Boundaries to avoid tight coupling or leaking backend internals
This is a design issue to decide an approach before implementation.