feat(inventory): add multi-country origin tracking

- Added `originCountries` field to `InventoryItem` model for multi-country origin support
- Updated `CreateInventoryDto` and `UpdateInventoryDto` with `originCountries` array field
- Modified `InventoryService` to handle `originCountries` in create and update operations
- Added `origin` field to `FlyerImportItem` response type for consistency
- Added `categoryId` field to `ParsedReceiptItem` DTO for improved receipt parsing
- Created database migration `20260524_add_origin_countries` for schema changes

backend/src/inventory/inventory.service.ts

@@ -91,6 +91,7 @@ export class InventoryService {
       location: data.location?.trim() || undefined,
       brand: data.brand?.trim() || undefined,
       origin: data.origin?.trim() || undefined,
+      originCountries: data.originCountries || undefined,
       receiptName: data.receiptName?.trim() || undefined,
       suitableFor: data.suitableFor?.trim() || undefined,
       comment: data.comment?.trim() || undefined,
@@ -128,6 +129,14 @@ export class InventoryService {
       updateData.brand = data.brand.trim();
     }
 
+    if (typeof data.origin === 'string') {
+      updateData.origin = data.origin.trim();
+    }
+
+    if (Array.isArray(data.originCountries)) {
+      updateData.originCountries = data.originCountries;
+    }
+
     if (typeof data.receiptName === 'string') {
       updateData.receiptName = data.receiptName.trim();
     }