palette-react: aria-activedescendant is not published for the initial highlighted option (cmdk 1.1.1) #68

Found while writing palette.a11y.test.tsx (#66, part of #64). On mount cmdk highlights the first option (aria-selected=true) but the combobox input has no aria-activedescendant until the highlight moves, so a screen reader does not hear the first option until the first arrow key. The test asserts this loosely (null or the option id). Options: report/fix upstream in cmdk, or drive cmdk's controlled value from the palette so the first option is published; then tighten the test.