No tuna. No paper towels. No Purell. No toilet paper. The shelves of every supermarket in the country have been picked clean. I’ve made three trips to the H.E.B. in San Angelo with no luck. Friends in California, New York, Virginia, and Tennessee report the same experience. It’s as if the apocalypse was announced, and we were all told to hoard tuna, paper towels, Purell, and toilet paper, and we…