Cheng Xin | Getty Images News | Getty Images Prediction markets giant Kalshi announced Friday it plans to launch perpetual futures contracts, starting with crypto perpetuals. They will give U.S. traders a regulated alternative to offshore platforms that have dominated this market. Perpetual futures, or "perps," are futures-style contracts with no fixed expiration date. Traders do not have to keep rolling from one dated contract into the next. Instead, the contracts are designed to track the price of the underlying asset continuously, with funding payments keeping the perp price aligned with the market. For instance, a crypto payments company or fund manager with exposure to bitcoin could use a regulated perpetual contract to hedge price risk without constantly managing contract expirations. If a firm expects to receive bitcoin next week, it could short a BTC perpetual to offset the risk that bitcoin falls before the payment is converted or booked.…