Unbatched stock is now represented as batch_id: null in Purchase Order rows and Purchase Order recipe rows

The batch_id field in purchase order row and purchase order recipe row batch_transactions now accepts null to represent unbatched stock.

Previously, unbatched stock was represented by a dedicated "Unbatched" batch record with its own ID, which had to be looked up via the batches API. Going forward, batch_id: null replaces this dedicated ID as the way to reference unbatched stock in these batch transactions. Existing unbatched batch IDs will continue to work for backward compatibility but will be normalized to null internally.

This applies to endpoints that allow creating or updating purchase order row and purchase order recipe row batch transactions, and endpoints that return them in responses - responses will also return batch_id: null for unbatched entries.

• GET https://api.katanamrp.com/v1/purchase_orders
• GET https://api.katanamrp.com/v1/purchase_orders/{id}
• POST https://api.katanamrp.com/v1/purchase_order_receive
• GET https://api.katanamrp.com/v1/purchase_order_rows
• GET https://api.katanamrp.com/v1/purchase_order_rows/{id}
• GET https://api.katanamrp.com/v1/outsourced_purchase_order_recipe_rows
• GET https://api.katanamrp.com/v1/outsourced_purchase_order_recipe_rows/{id}
• PATCH https://api.katanamrp.com/v1/outsourced_purchase_order_recipe_rows/{id}
• POST https://api.katanamrp.com/v1/outsourced_purchase_order_recipe_rows/{id}

Example request body / response body:

{
  "batch_transactions": [
    { "batch_id": 5, "quantity": 7 },
    { "batch_id": null, "quantity": 3 }
  ]
}

This change currently applies to Purchase Order rows and Purchase Order recipe rows and will be rolled out to other domains in upcoming updates.