curl --request POST \
  --url http://localhost:3000/v1/products/{id}/adjust-inventory \
  --header 'Content-Type: application/json' \
  --data '
{
  "inventory_group_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "quantity": 1
}
'

{
  "success": true,
  "action": "created",
  "inventory_item_id": "<string>",
  "previous_quantity": 123,
  "new_quantity": 123
}