-- ===========================================================================
-- Migration: Vehicle acquisition cost
-- Date: 2026-07-30
--
-- The vehicle register never captured what a vehicle cost, so buying one never
-- reached the books. This column records the acquisition cost; adding a vehicle
-- as a real purchase now expenses it (Dr Vehicle expense, Cr Cash/Payable) — the
-- farm's chosen "expense at purchase" treatment. Idempotent.
-- ===========================================================================

ALTER TABLE vehicles
  ADD COLUMN IF NOT EXISTS purchase_cost DECIMAL(12,2) NULL AFTER acquired_on;