milestone 23: restore the focus ring on select options, check layer order, close preflight gaps

specs/milestone-23.md

@@ -465,21 +465,21 @@ That last clause is the check that keeps the scope honest, and it holds:
 `react-aria-components` is imported only by the four `ui/` wrappers. A RAC
 `Button` in a feature file would still be a breach.
 
-### The focus-ring floor does not reach a listbox option
+### The focus-ring floor was briefly amended on a false premise
 
-`Select.tsx` gives the trigger the shared focus ring, but the popover's options
-show keyboard focus as a background inversion — `primary` behind `primaryText`
-— with the outline removed, and the listbox itself has no ring. That is the
-selection-highlight convention for a listbox and a strong-contrast indicator,
-but it is not ruling 3's 2px focus-token outline, and the code is in breach as
-the ruling is written. Two things make the ring the wrong mechanism here rather
-than a missing one: an option inside a scrolling popover clips its own outline,
-and RAC drives option focus through its `isFocused` render prop, so a
-`:focus-visible` rule — which is how the shared `focusRing` is written — may
-never match the element at all. The floor is amended to cover controls that
-take DOM focus; a listbox option instead requires a focus indicator with a
-contrast change against both schemes, which the inversion provides. Every other
-interactive element, the trigger included, keeps the ring.
+S2 left the Select's options with their outline removed, showing keyboard focus
+as a background inversion alone. This section previously amended ruling 3 to
+excuse that, arguing RAC drives option focus through an `isFocused` render prop
+so a `:focus-visible` rule could never match. That argument is wrong.
+`useSelectableItem` gives options a roving `tabIndex` and focuses the option's
+own DOM node (`react-aria/dist/private/selection/useSelectableItem.mjs:64`),
+which `ListBoxItem` spreads onto its element — so `:focus-visible` matches and
+the ring was simply missing. The amendment is withdrawn and ruling 3 stands
+unchanged. `Select.tsx` now composes the shared inset ring onto every option:
+inset because an option flush against a scrolling popover clips an outset
+outline, and recoloured to `primaryText` on the highlighted row because the
+focus token is the same blue that row paints behind it. The inversion stays as
+the listbox convention; it is no longer the only indicator.
 
 ### Two notes for S3