Add پس کرایه (freight collect) on shipping cost groups.

When enabled, checkout shipping amount is 0 while customers still see the پس کرایه label.

Co-authored-by: Cursor <cursoragent@cursor.com>

prisma/schema.prisma

@@ -1268,6 +1268,7 @@ model ShippingCostGroup {
   sortOrder    Int                          @default(0) @map("sort_order")
   isActive     Boolean                      @default(true) @map("is_active")
   isDefault    Boolean                      @default(false) @map("is_default")
+  pasKraye     Boolean                      @default(false) @map("pas_kraye")
   createdAt    DateTime                     @default(now()) @map("created_at") @db.Timestamptz(6)
   updatedAt    DateTime                     @default(now()) @updatedAt @map("updated_at") @db.Timestamptz(6)
   business     Business                     @relation(fields: [businessId], references: [id], onDelete: Cascade, onUpdate: NoAction)