The latest addition to the jazz line-up in Healdsburg comes from a young talent still in high school. Kai Devitt-Lee, who’ll be a junior at Healdsburg High next fall, will be showing off his still-developing skills on jazz guitar at the Palette Art Café on alternate Sundays this summer. (Update: Kai has been upgraded to weekly appearances at Palette, every Sunday this summer.) Kai, still only 15 years old, has