POST/PUT/DELETE for items: create mints the itemcode from the
configured prefix plus the flushed row id, update refuses
quantityonhand (ledger-managed - restock/adjust arrive next stage),
delete soft-retires. The image upload/serve/delete trio replicates the
models.py pattern into instance/printedpartsimages/ with a public GET.
PrintedItemDetail follows the unified detail skeleton (hero photo,
info list, transaction history table); PrintedItemForm covers
create/edit plus photo management on edit.
cb367a38f9