Amazon is expanding access to a program called  Shop Direct that lets U.S. customers discover and buy products not sold in its own online store. The retail giant on Wednesday said it will now support third-party product feeds, which merchants use to provide information about their inventory, pricing, and catalog to other partners. With this information, Amazon can direct shoppers to a merchant’s website via its search results or its AI shopping assistant, Rufus, and even let customers use AI to make a purchase. The company has added support for third-party product feeds from Feedonomics, Salsify, and CedCommerce, which provide Amazon access to merchants’ inventory and product information in real time. More feed providers will be supported in time, and an Amazon merchant portal with a merchant-direct feed is said to be coming soon.…