As “pop-ups” go, the one coming to the Port of Seattle is pure pandemic. The U.S. Department of Agriculture will soon be offering $200 to $400 bounties for containers packed with agricultural goods delivered to a 49-acre pop-up site near the Seattle shipping terminals. The pop-up site is a small part of the response to what has become a sprawling, pandemic-driven problem. Shipping containers are in demand by Asian manufactures looking to ship to product-hungry Americans, so much so that they’re being shipped back to Asia empty. American farmers, meanwhile, can’t get container space they need t…