fix: re-render picker preview on resize

@@ -73,6 +73,7 @@ func (m *Model) SetSize(w, h int) {
 	m.width = w
 	m.height = h
 	m.preview.SetSize(m.previewWidth(), h-2)
+	m.renderPreview()
 }
 
 // SetTheme repaints the picker with a new theme.