feat(ADM-018): completed feature

work/artifacts/F-019/documenter.md

@@ -0,0 +1,25 @@
+# Documenter — F-019 Promotions v1
+
+## Summary
+Promotions v1 adds server-side promo code definitions and validation. Cart stores only a selected `promoCode`; discount amounts are recalculated from current cart totals.
+
+## Public API notes
+
+| Route | Access | Result |
+|---|---|---|
+| POST /promotions | admin only | Creates or updates a promo code |
+| POST /cart/promo-code | authenticated | Applies one promo code to the current cart |
+
+## Rules
+- Promotion types: `percent` and `fixed_amount`.
+- Percent values are basis points; fixed values are cents and capped at cart total.
+- Validity checks: active flag, time window, usage limit.
+- No stacking in v1: one promo code per cart.
+- Client-supplied discount amounts are ignored.
+
+## Evidence
+- `work/artifacts/F-019/architect.md`
+- `work/artifacts/F-019/implementer.md`
+- `work/artifacts/F-019/reviewer.json`
+- `work/artifacts/F-019/security.json`
+- `work/artifacts/F-019/qa.json`