-- ============================================================================
-- Which egg store a sale's egg line item was actually sold from — mirrors
-- sale_items.grade exactly (same nullable, "only meaningful for egg lines"
-- treatment). Lets an invoice round-trip through edit without losing which
-- store its eggs came from, and lets each line be validated against that
-- specific store's stock, not just a farm-wide default.
-- ============================================================================

ALTER TABLE sale_items
  ADD COLUMN store VARCHAR(64) NULL AFTER grade;