The program invoice item was stored with unit_price = original programFee,
then recalculateTotals() summed items and overwrote total_amount back to
the original — so the printed invoice showed the pre-override amount.

Fix: apply the override delta directly to the item's unit_price so the item
row and invoice total are consistent. Metadata now stores original_price =
programFee (per-item, not order total) for the strikethrough display on print.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>