Let a segmented row answer, and inset a list's dividers

Plan step 19, containment.md C-08, C-21, C-22 and C-16. The segmented
fill was declared unlayered, so it beat every state layer in
@layer components and a segmented row lit up for nothing: it now sits in
the layer, `:where()`d to weigh nothing, ahead of the state rules. Its
tone is `surface`, which is ListTokens' ItemSegmentedContainerColor, and
a keyboard-focused row morphs to the large corner like a pressed one.
`<x-list dividers>` draws ListTokens' 16dp-inset rule instead of a
full-bleed `divide-y`.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9

resources/views/components/list.blade.php

@@ -1,9 +1,11 @@
 {{-- An M3 list: `<x-list-item>`s, one under another.
 
      Plain by default — the items sit on the surface around them, with `dividers` between them if
-     asked. `segmented` is M3 Expressive's list: each item its own surface-container tile, 2px
-     apart, with small corners that open to large at the ends and while hovered, pressed or
-     selected (ListTokens, androidx Compose Material 3, Apache-2.0).
+     asked, inset 16px from both ends as ListTokens' `DividerLeadingSpace`/`DividerTrailingSpace`
+     say (resources/css/components/list.css draws them). `segmented` is M3 Expressive's list: each
+     item its own surface tile, 2px apart, with small corners that open to large at the ends and
+     while hovered, pressed, focused or selected (ListTokens, androidx Compose Material 3,
+     Apache-2.0).
 
      A plain list is a `role="list"` of `listitem`s. `selectable` (or `selection="single"` /
      `selection="multi"`) makes it the list a person chooses from: M3 maps single- and
@@ -38,11 +40,11 @@
     role="{{ $selection === null ? 'list' : 'listbox' }}"
     @if ($selection === 'multi') aria-multiselectable="true" @endif
     data-list="{{ $segmented ? 'segmented' : 'plain' }}"
+    @if ($dividers && ! $segmented) data-dividers @endif
     @if ($label) aria-label="{{ $label }}" @endif
     {{ $attributes->class([
         'flex flex-col',
         'gap-0.5' => $segmented,
-        'divide-y divide-outline-variant' => $dividers && ! $segmented,
     ]) }}
 >
     {{ $slot }}