feat(ADM-018): completed feature

work/artifacts/F-010/documenter.md

@@ -0,0 +1,19 @@
+# Documenter — F-010 Variants, SKU/EAN and product rich data
+
+done -> work/artifacts/F-010/documenter.md
+
+## Documentation updated
+- `project/README.md`
+
+## Covered
+- Product variant error code `PRODUCT_VARIANT_CODE_EXISTS`.
+- Variant endpoints under `/products/:id/variants`.
+- Rich data endpoint `/products/:id/rich-data`.
+- Variant SKU/EAN uniqueness.
+- Nutrition provenance sources: `manual`, `manufacturer`, `openfoodfacts`.
+- Manual nutrition protection from external-source overwrites.
+- Explicit out-of-scope note: no stock, prices, images, or external sync job.
+
+## Verification
+- `cd project && npm run lint` — PASS after README Prettier normalization.
+- `./scripts/verify.sh` — PASS from repository root before documentation close.