Brand no longer re-derives the product from maker and design (key-first pick);
CreateLot(product) is the one writer of Lot.Product. The census duplicate-brand
block and the key-order tie-break test go with the derivation they policed.
Unverified at this commit; build and tests follow.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>