The Riverside bookstore Cellar Door Books was notified Tuesday that it must leave Canyon Crest Towne Centre by Feb. 28. (That was extended Friday to March 31 after I inquired.) The owner must scramble to find a replacement space and move. Founded in 2012, Cellar Door is touted as the only independent bookstore in the Inland Empire devoted to new books. I write about the store’s travails in a newsy Sunday column.