PO_SUBMITTED: managers only, submitter no longer copied
PAYMENT_SENT: submitter only (it is a receipt prompt, not a manager action)
PARTIAL_RECEIPT_CONFIRMED: managers now notified via new event type
RECEIPT_CONFIRMED: unchanged (managers + accounts)
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Subject line now reads 'Purchase Order XXXX' instead of 'PO XXXX'.
Each email includes a recipient-specific deep-link action button,
a PO summary card (number, title, submitter, vendor, vessel, cost centre, total),
and a line items table with qty/unit price/GST/line total.
notify() fetches enriched data internally so no call sites change.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
