Implement global vendor mappings with bundle support and seen-based ignore

CLAUDE.md

@@ -130,3 +130,28 @@ type PricelistItem struct {
 - Главная страница должна вести на `/admin/pricing`.
 - В UI не должно быть ссылок на конфигуратор, проекты и экспорт.
 - **НЕ использовать SSE** - только фоновые задачи через Task Manager.
+
+## Vendor Mapping Rules (2026-02-18)
+
+- `lot_partnumbers` is the canonical mapping contract for external configurator.
+- Do not reintroduce multi-row mapping for one key: one `(vendor, partnumber)` -> one `lot_name`.
+- Resolver behavior is fixed:
+  - first exact `vendor + partnumber`,
+  - then fallback `vendor='' + partnumber`.
+- Composite vendor partnumbers must be implemented via internal bundle tables:
+  - `qt_lot_bundles`
+  - `qt_lot_bundle_items`
+- Bundle LOT is internal and hidden in regular LOT UI by default.
+- Ignore behavior:
+  - do not use `stock_ignore_rules` for new logic,
+  - use `qt_vendor_partnumber_seen.is_ignored` (cross-source).
+- Client compatibility requirement:
+  - client still consumes LOT-based pricelists,
+  - bundle expansion/allocation happens only inside PriceForge warehouse calculations.
+
+### Related modules
+- Migration: `migrations/023_vendor_partnumber_global_mapping.sql`
+- Service/API: `internal/services/vendor_mapping.go`, `internal/handlers/pricing.go`
+- Resolver: `internal/lotmatch/matcher.go`
+- Warehouse calc: `internal/warehouse/snapshot.go`
+- Stock import seen+ignore: `internal/services/stock_import.go`