Why a variant's price is what it is: every price step, with its date, actor and reason.

One row per price or reference-price step of one variant, newest first, from the price history Magistry keeps for every variant. attribution says how the step is known: receipt when a Magistry receipt set it (its receipt_id, action_id, actor, reason and approved_by are the ones POST /api/v1/receipts returns), writer when only the writer's stamp names it, observed when a sync read it from the shop, first_seen for the first price we recorded and unknown when nothing recorded who changed it — an actor is never guessed. receipt_candidates counts the price acts that could have set the step; above 1 the newest one before the step is shown.