Implement a Standard Product Supplier Integration (SPSI) to receive ezyVet purchase orders and return receive invoices

Steps

1. Implement a partner product-catalog endpoint that accepts URL-encoded, array-style query params (e.g. ?code=[]&name=[abc,def]) and returns an empty {"products": []} rather than an error when nothing matches
2. Provide a category endpoint so clinics can browse/search your catalog by product category
3. Receive purchase orders (containing purchase_order_item_list with ids, quantities, and the clinic's ownership_id) sent from ezyVet when a clinic places an order
4. Return a receive invoice via the v2/jobqueue endpoint, mapping each line's purchase_order_item_id back to the original PO item and its ownership_id to the correct stock location
5. Support batch-tracked products by including a batch array (name, expiry, quantity) per receive-invoice line item when applicable
6. Round tax/total_tax fields to 4 decimal places, and set the line quantity to the number of outers/containers, not inner units