Moves the ItemInventory upsert from confirmReceipt (CLOSED) to approvePo
(MGR_APPROVED) so site inventory is visible as soon as a purchase order
is manager-approved, without waiting for full closure.
- approvePo: fetch lineItems, upsert ItemInventory per site PO line item
that has a productId; revalidate the site admin path.
- confirmReceipt: remove the now-redundant inventory update block.
- Rename approvepo → approvePo for consistency (fixes import mismatch
in the existing integration test file).
- Add three integration test cases covering: site PO inventory increment,
line items without productId are skipped, vessel-only POs are untouched.
Fixes#7
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>