design-template-pick.ts says which decorated template a page of the auto layout is laid on. Every built-in theme belongs to an archetype (THEME_ARCHETYPE, the five new themes to their own five), and a book picks from that archetype's spreads and from those of the archetypes that sit well beside it (ARCHETYPE_KIN). A template that would leave a photo frame empty, lose the story, draw a map with nothing to draw, repeat the page before or follow a busy page loudly is never a candidate; of the rest the best fit wins: the photos all used, the theme's own archetype, the story fitting its frame (bodyCapacity measures each frame once per format and face), the first frame the shape of the first photo, not used a few pages back, and calm where the book should breathe. Equal ones are chosen by the design's seed. chunkPhotos cuts an entry's photos into page-sized parts that leave no frame empty, and pickCoverTemplate does the same for the cover.
@trek/shared
Single source of truth for TREK's API contracts, expressed as Zod schemas and consumed by both the server (request validation + inferred DTO types) and the client (typed requests/responses).
This package is part of the incremental NestJS + React 19 migration (see the "Brownfield Rewrite" board). It is intentionally dormant until modules start importing it — adding it changes nothing for users.
Rules
- One folder per domain:
src/<domain>/<domain>.schema.ts(+.spec.ts). - Domain-agnostic building blocks live in
src/common/. - A route is only considered migrated once its contract lives here.
- Schemas are the source of truth; server DTOs and client types are inferred from them
(
z.infer<typeof schema>), never hand-duplicated.
Consumption (dev)
Both apps resolve @trek/shared to this package's TypeScript source:
- Server (
tsx): viapathsinserver/tsconfig.json. - Client (
vite): viaresolve.aliasinclient/vite.config.ts(+pathsfor the type-checker).
Production packaging (Docker / workspace wiring) is introduced in card F2, when the server first depends on this package at runtime. Until then prod builds are untouched.
Not yet here
The canonical error envelope is finalised in card F5 (it must match TREK's current Express error responses byte-for-byte), so it is deliberately not invented in F1.