Announce a selectable list as M3's list box of options

Plan step 12, containment.md C-03. `selected` was colour alone on a
`listitem`, which cannot carry a selected state at all. `<x-list
selectable>` (or `selection="single|multi"`) now makes the container a
`role="listbox"` and each item an `option` with `aria-selected`; a plain
list keeps `role="list"` and marks a selected item `aria-current`. A
selected option draws a trailing check as M3's second cue, which
`icon-right` replaces. The item reads its list's mode with `@aware`.

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

resources/boost/skills/livewire-material-development/SKILL.md

@@ -433,6 +433,8 @@ A card or list item that opens something is a **row**: `data-list-row` on it and
 
 `<x-list>`: `label`, `dividers`, `segmented` (M3 Expressive: separate tiles 2px apart). `<x-list-item>`: `title` (or slot), `overline`, `description`, leading `icon` / `avatar` (image URL or initials) / `image` / `leading` slot, trailing `trailing` text / `icon-right` / `end` slot, `link` (the whole item becomes a row that opens it), `selected`, `disabled`. One-, two- and three-line heights follow from the content.
 
+A list a person chooses from is `<x-list selectable>` (or `selection="single"` / `selection="multi"`): M3 maps those to a **list box** of **options**, so the container becomes `role="listbox"` (`aria-multiselectable` when multi) and each item an `option` announcing `aria-selected`. A selected option also draws a trailing check — M3 never allows colour as the only cue — which `icon-right` or a leading checkbox replaces. A plain list stays `role="list"`, where `selected` is `aria-current`. `disabled` renders no link and announces `aria-disabled`.
+
 ```blade
 <x-list segmented label="Files">
     @foreach ($files as $file)

resources/views/components/list-item.blade.php

@@ -15,7 +15,12 @@
      control that opens — see resources/js/list-rows.js. `selected` (true) is M3's selected item,
      in secondary-container; `disabled` greys it to 38%, drops its link and announces it
      `aria-disabled` — M3's states model treats disabled as not interactive, so a disabled item
-     answers neither the pointer nor the keyboard. --}}
+     answers neither the pointer nor the keyboard.
+
+     It takes its role from the `<x-list>` around it: a `listitem` in a plain list, where
+     `selected` is `aria-current`, and an `option` announcing `aria-selected` in a `selectable`
+     one. M3 asks for two cues on a selected item, never colour alone, so a selected option also
+     draws a trailing check unless `icon-right` says otherwise. --}}
 
 @props([
     'title' => null,
@@ -33,14 +38,23 @@
     'disabled' => false,
 ])
 
+{{-- Whether the `<x-list>` around it is one a person chooses from, and how many it takes. --}}
+@aware([
+    'selectable' => false,
+    'selection' => null,
+])
+
 @php
     $isLink = filled($link) && ! $disabled;
     $lines = (filled($overline) ? 1 : 0) + (filled($description) ? 1 : 0);
     $initials = filled($avatar) && ! str_contains((string) $avatar, '/') && ! str_contains((string) $avatar, '.');
+    $option = $selectable || $selection !== null;
+    $check = $option && $selected && blank($iconRight);
 @endphp
 
 <div
-    role="listitem"
+    role="{{ $option ? 'option' : 'listitem' }}"
+    @if ($option) aria-selected="{{ $selected ? 'true' : 'false' }}" @elseif ($selected) aria-current="true" @endif
     data-list-item
     @if ($isLink) data-list-row @endif
     @if ($selected) data-selected @endif
@@ -98,5 +112,7 @@
 
     @if ($iconRight)
         <x-livewire-material::icon :name="$iconRight" :class="\Illuminate\Support\Arr::toCssClasses(['size-6', 'text-on-surface-variant' => ! $selected && ! $disabled])" />
+    @elseif ($check)
+        <x-livewire-material::icon name="check" class="size-6" />
     @endif
 </div>

resources/views/components/list.blade.php

@@ -5,18 +5,38 @@
      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).
 
-     It is a `role="list"`; for keyboard walking between rows, `j`/`k` or arrows, the application
-     can use `data-list` (resources/js/list-rows.js marks rows; a list keyboard arrives with the
-     list-detail pane). `label` names the list. --}}
+     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
+     multi-select lists on the web to a **list box** of **options** with a selected state
+     (docs/reference/m3/components-actions-communication-containment.md § Lists → Accessibility),
+     so the container becomes `role="listbox"` (`aria-multiselectable` when multi) and each item
+     an `option` that announces `aria-selected`. A selected option also draws a trailing check, so
+     selection is never colour alone; give the items a leading checkbox or radio instead and pass
+     `icon-right` to keep the check off.
+
+     For keyboard walking between rows, `j`/`k` or arrows, the application can use `data-list`
+     (resources/js/list-rows.js marks rows; a list keyboard arrives with the list-detail pane).
+     `label` names the list. --}}
 
 @props([
     'segmented' => false,
     'dividers' => false,
     'label' => null,
+    'selectable' => false,
+    'selection' => null,
 ])
 
+@php
+    $selection = match (true) {
+        in_array($selection, ['single', 'multi'], true) => $selection,
+        $selectable || $selection !== null => 'single',
+        default => null,
+    };
+@endphp
+
 <div
-    role="list"
+    role="{{ $selection === null ? 'list' : 'listbox' }}"
+    @if ($selection === 'multi') aria-multiselectable="true" @endif
     data-list="{{ $segmented ? 'segmented' : 'plain' }}"
     @if ($label) aria-label="{{ $label }}" @endif
     {{ $attributes->class([

resources/views/showcase/sections/containment.blade.php

@@ -40,9 +40,17 @@
                     <x-list-item title="Chiara Rossi" avatar="CR">
                         <x-slot:end><x-button icon="more_vert" tooltip="More" /></x-slot:end>
                     </x-list-item>
+                    <x-list-item title="Dan Fischer" description="Invitation withdrawn" avatar="DF" link="#containment" disabled />
                 </x-list>
             </div>
             BLADE,
+        'A list to choose from' => <<<'BLADE'
+            <x-list selectable label="Expiry" class="w-full max-w-sm">
+                <x-list-item title="One hour" :selected="false" />
+                <x-list-item title="Three days" :selected="true" />
+                <x-list-item title="Thirty days" :selected="false" />
+            </x-list>
+            BLADE,
         'Dividers and collapse' => <<<'BLADE'
             <div class="w-full space-y-4">
                 <x-collapse title="How long do links last?" icon="schedule" open>