Refund-related features

[agritheory]

Refunds / returned items will be handled via automated reporting - ideally scheduled for overnight processing.

Since we don't know anything from Stripe or Authorize about Itemization , we can limit the impact to the payable/receivable and handle it with a full or partial reversing payment entry. Ideally these would be linked by an existing transaction ID, but that's not required to make it balance.