PARTIAL SAVE: writes ONLY the 'Marketplace' field of TitlePublicConfigurationModel; all other v1/v2 fields stay untouched. Player-to-player marketplace (v2) — fixed-price listings (price = ResourceBundle), auctions (single-axis bids), buy orders (escrowed payment), and direct trades/gifts. Configures the audience gate, open-window schedule, price composition policy (reusing the same EntryResourceRule whitelist as Match), commission policy (percent/min, burn or ledger sink, per-goods-catalog overrides), item tradability lists, and per-mechanic settings/limits. Distinct from Store (title-sold SKUs) and DealOffer (promotions): here players trade with each other. Everything offered is escrowed at creation; commission is taken at settlement.