American TV storytelling sometimes struggles with a good New Years plot. Or it did until Linda Bloodworth-Thomason fired up her typewriter in 1989 to deliver the January 1, 1990 episode of Designing Women entitled “The First Day of the Last Decade of the Entire 20th Century.” It is pure art, as performed by the four original actresses: Dixie Carter, Delta Burke, Jean Smart and Annie Potts. It’s written by creator and showrunner Linda Bloodworth Thomason, directed by co-creator husband Harry Thomason. Yup, this was the one that included Charlene's dream with Dolly Parton. And then there’s the hair…