v4.50.0 — The Market Layer

The market half of the two-layer rarity system is now built (still switched OFF until it clears the accuracy gate). When it turns on: a common casting that genuinely trades like a rarer one can earn a market elevation — but only on real evidence (its sold price holding several times above a fresh mainline, across multiple re-checks), it's capped at RARE, it eases back down if the market cools (no flip-flopping), and it shows an honest observation log of every re-price on the Market tab instead of a made-up chart. A casting's true identity never changes underneath it. Nothing in your garage moves yet.