Just about a decade ago, Valerie Wolzien, who was then a housewife, began composing her first mystery novel on a warped old card table in her basement. All her subsequent whodunits pay implicit tribute to that hard-won apprenticeship: Each of them has the conciseness and seamlessness that only revision can bring. In this engaging home construction drama which has all the excitement of a slippery roof, contractor Josie finds herself twice famous and once accused. After a PBS remodeling series invades her site, Ms. Pigeon fights back intrusive media people. But when the hostess of the show turns up as a bloody corpse, Josie's curses turn into pleas. Straight-edge sleuthing