feat: add AGENTS.md for all packages and apps (9 files)

packages/cms-core/AGENTS.md

@@ -0,0 +1,40 @@
+# @repo/cms-core — Payload CMS Definition
+
+All Payload configuration lives here: payload.config.ts, collections, globals, hooks, access control. The `apps/cms` app is a thin shell that imports this config.
+
+## Hook Rules
+
+| Category | Location | Examples |
+|---|---|---|
+| CMS-operational | Stay in hook | Slugify, image resize, default values |
+| Business logic | Delegate to use case | Notifications, validation, cross-domain updates |
+
+### DO
+
+- Keep hooks thin (max 5-10 lines)
+- Import use cases from `@repo/core/application`
+- Map Payload hook args to use case input types
+
+### DON'T
+
+- Import from `@repo/core/infrastructure`
+- Put business validation in hooks
+- Call external services directly from hooks
+- Duplicate logic that exists in a use case
+
+## Adding a New Collection
+
+1. Create folder: `src/collections/{name}/`
+2. Create: `index.ts` (CollectionConfig), `fields.ts`
+3. Optionally: `hooks/`, `access/`
+4. Import in `src/payload.config.ts` collections array
+5. Export from `src/index.ts`
+
+## Adding a Hook That Calls a Use Case
+
+1. Create `src/collections/{name}/hooks/{hook-name}.ts`
+2. Import use case from `@repo/core` (application layer only)
+3. Map Payload's hook args to use case input
+4. Call use case, return data
+
+**Rule of thumb:** If deleting the hook would break a business requirement, the logic must be in a use case.