feat(eidos): port Listbox (embedded selection list)

#131. Eidos wrapper + types + recipe + canonical-depth demo. Soma owns
single/multi selection (value as string[]), roving-tabindex keyboard
nav (Arrow + Home/End + typeahead + Ctrl+A), Field-merged flags
(disabled/readonly/required/invalid), hidden form inputs. Eidos adds
the visual surface and exposes variant + size + color.

Reference parity (no air baseline — port directly from soma):

| Feature | soma | react-aria | Headless UI | bits-ui | this port |
|---|---|---|---|---|---|
| Single + multiple selection | ✓ | ✓ | ✓ | ✓ | ✓ |
| bind:value (controlled) | ✓ | ✓ | ✓ | ✓ | ✓ |
| Typeahead + Arrow / Home / End | ✓ | ✓ | ✓ | ✓ | ✓ |
| Loop nav | ✓ | ✗ | ✗ | ✗ | ✓ |
| Section / Group + label | ✓ | ✓ | ✗ | ✓ | ✓ |
| Ctrl+A select-all (multi) | ✓ | ✓ | ✗ | ✗ | ✓ |
| Form participation (hidden inputs) | ✓ | ✗ | ✓ | ✗ | ✓ |
| Field.Provider merge (disabled/invalid/…) | ✓ | ✗ | ✗ | ✗ | ✓ |
| Horizontal orientation | ✓ | ✓ | ✓ | ✓ | ✓ |
| Item indicator (✓ glyph) | ✓ | ✓ | ✗ | ✓ | ✓ shared partial |
| Drag-to-reorder | ✗ | ✓ | ✗ | ✗ | ⚠ deferred |
| Async / infinite loading | ✗ | ✓ | ✗ | ✗ | ⚠ deferred |
| selectionBehavior (toggle/replace) | ⚠ implicit | ✓ | ✗ | ✓ | ⚠ deferred |
| PageUp/Down nav | ✗ | ✓ | ✗ | ✗ | ⚠ deferred |

Parts (5): Listbox (Root, replaces soma's Provider name), Item,
ItemIndicator, Group, GroupLabel.

Variant set:
- variant: ControlVariant (`'surface' | 'outline' | 'ghost'`), default 'surface'
- size: xs..xl (5-step canonical form-control scale)
- color: ColorRole (primary/secondary/neutral/affirm/fulfill/risk/threat/loss)
- block: stretch to container width

Cross-component reuse:
- `ItemIndicator` shares the menu-indicator visual (`a2709476`) — ✓ glyph
  identical to standalone Checkbox and Dropdown/Context Menu
  CheckboxItems. CSS-only difference: shown only inside
  `[data-listbox-item][data-selected]`.
- Item row hover / highlight tokens mirror Combobox.Item /
  Command.Item — the form-control surface family stays coherent.

Disambiguation note (in index.ts comment):
- Listbox: atomic options, text rows, no inner interactive elements
  (ARIA forbids interactive descendants inside role="listbox")
- GridList: rows with buttons / links / checkboxes inside (2D nav)
- Select / Combobox: closed picker surface (Listbox-like dropdown)

Gotcha: listbox.svelte and listbox-item.svelte rename `children` to
`bodyContent` on destructure to avoid shadowing the inner
`{#snippet children}` block (same recursion trap documented in
`feedback_button_consumer_pattern.md` Rule 3).

Demo: 6 tabs at canonical depth — Live wires all soma + eidos props,
all 3 ControlVariant chips, 5 size chips, 8 ColorRole chips, single +
multi mode toggle, RTL/horizontal toggle. Sidebar entry added under
Forms (between Combobox and Calendar).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/uix/eidos/components/listbox/index.ts

@@ -0,0 +1,69 @@
+// Listbox — eidos compound API.
+//
+//   import { Listbox } from '$uix/eidos/components/listbox';
+//
+//   <Listbox bind:value selectionMode="single">
+//     <Listbox.Item value="apple">
+//       <Listbox.ItemIndicator />
+//       Apple
+//     </Listbox.Item>
+//     <Listbox.Item value="banana" disabled>
+//       <Listbox.ItemIndicator />
+//       Banana
+//     </Listbox.Item>
+//     <Listbox.Group>
+//       <Listbox.GroupLabel>Citrus</Listbox.GroupLabel>
+//       <Listbox.Item value="orange">
+//         <Listbox.ItemIndicator />
+//         Orange
+//       </Listbox.Item>
+//     </Listbox.Group>
+//   </Listbox>
+//
+// Soma owns single/multi selection (value as string[]), roving-tabindex
+// keyboard nav (Arrow + Home/End + typeahead + Ctrl+A), Field
+// integration (disabled/readonly/required/invalid OR-merged), and
+// hidden form inputs. Eidos paints the visual surface and exposes
+// `variant` (ControlVariant — surface/outline/ghost), `size` (xs..xl),
+// `color` (ColorRole). The ItemIndicator ✓ glyph mirrors the shared
+// menu-indicator partial used by Dropdown/Context Menu CheckboxItems.
+//
+// Disambiguation: use Listbox for atomic options (text rows, no inner
+// interactive elements). For row-with-button/link/checkbox patterns
+// use `GridList` instead (ARIA forbids interactive descendants inside
+// role="listbox").
+import ListboxRoot from './listbox.svelte';
+import Item from './listbox-item.svelte';
+import ItemIndicator from './listbox-item-indicator.svelte';
+import Group from './listbox-group.svelte';
+import GroupLabel from './listbox-group-label.svelte';
+
+type ListboxNamespace = typeof ListboxRoot & {
+	Item: typeof Item;
+	ItemIndicator: typeof ItemIndicator;
+	Group: typeof Group;
+	GroupLabel: typeof GroupLabel;
+};
+
+const Listbox = ListboxRoot as ListboxNamespace;
+Listbox.Item = Item;
+Listbox.ItemIndicator = ItemIndicator;
+Listbox.Group = Group;
+Listbox.GroupLabel = GroupLabel;
+
+export { Listbox };
+export default Listbox;
+
+export type {
+	ListboxProps,
+	ListboxItemProps as ItemProps,
+	ListboxItemIndicatorProps as ItemIndicatorProps,
+	ListboxGroupProps as GroupProps,
+	ListboxGroupLabelProps as GroupLabelProps,
+	ListboxSize,
+	ListboxVariant,
+	ListboxColor,
+	ListboxSelectionMode,
+	ListboxProviderSnippetProps,
+	ListboxItemSnippetProps
+} from './types';

src/uix/eidos/components/listbox/listbox-group-label.svelte

@@ -0,0 +1,7 @@
+<script lang="ts">
+	import * as Listbox from '$soma/components/listbox';
+	import type { ListboxGroupLabelProps } from './types';
+	let { children, ...rest }: ListboxGroupLabelProps = $props();
+</script>
+
+<Listbox.GroupLabel {...rest}>{@render children?.()}</Listbox.GroupLabel>

src/uix/eidos/components/listbox/listbox-group.svelte

@@ -0,0 +1,7 @@
+<script lang="ts">
+	import * as Listbox from '$soma/components/listbox';
+	import type { ListboxGroupProps } from './types';
+	let { children, ...rest }: ListboxGroupProps = $props();
+</script>
+
+<Listbox.Group {...rest}>{@render children?.()}</Listbox.Group>

src/uix/eidos/components/listbox/listbox-item-indicator.svelte

@@ -0,0 +1,7 @@
+<script lang="ts">
+	import * as Listbox from '$soma/components/listbox';
+	import type { ListboxItemIndicatorProps } from './types';
+	let { children, ...rest }: ListboxItemIndicatorProps = $props();
+</script>
+
+<Listbox.ItemIndicator {...rest}>{@render children?.()}</Listbox.ItemIndicator>

src/uix/eidos/components/listbox/listbox-item.svelte

@@ -0,0 +1,14 @@
+<script lang="ts">
+	import * as Listbox from '$soma/components/listbox';
+	import type { ListboxItemProps } from './types';
+	// Rename `children` to `bodyContent` to avoid shadowing the inner
+	// `{#snippet children}` block — same recursion gotcha documented in
+	// `feedback_button_consumer_pattern.md`.
+	let { children: bodyContent, ...rest }: ListboxItemProps = $props();
+</script>
+
+<Listbox.Item {...rest}>
+	{#snippet children(snippetProps)}
+		{@render bodyContent?.(snippetProps)}
+	{/snippet}
+</Listbox.Item>

src/uix/eidos/components/listbox/listbox.css

@@ -0,0 +1,211 @@
+/*
+ * Listbox recipe.
+ *
+ *   [data-listbox]                → root container
+ *   [data-listbox-item]           → option row
+ *   [data-listbox-item-indicator] → ✓ glyph on selected items
+ *   [data-listbox-group]          → group container
+ *   [data-listbox-group-label]    → muted group label
+ *
+ * Sizes — xs..xl on the root; cascades to item height + font-size.
+ * Variant `'surface' | 'outline' | 'ghost'` (ControlVariant).
+ * Color cascades the accent for selected-item highlight + focus ring.
+ *
+ * Cross-component reuse:
+ *   - The ItemIndicator visual is the canonical check glyph — same as
+ *     [data-checkbox-indicator] / menu-item indicators. Painted here as
+ *     a filled accent square with white ✓ on selected items.
+ */
+
+[data-listbox] {
+	--_listbox-item-height: var(--control-height-md);
+	--_listbox-item-px: var(--space-3);
+	--_listbox-item-font-size: var(--font-size-sm);
+	--_listbox-accent: var(--color-primary-solid);
+	--_listbox-accent-soft: var(--color-primary-element);
+	--_listbox-accent-text: var(--color-content-on-solid);
+
+	display: flex;
+	flex-direction: column;
+	gap: var(--space-1);
+	padding: var(--space-1);
+	border: 1px solid var(--color-border-default);
+	border-radius: var(--radius-md);
+	background: var(--color-surface-default);
+	color: var(--color-content-primary);
+	font-family: var(--font-ui);
+	font-size: var(--_listbox-item-font-size);
+	line-height: var(--leading-ui);
+	outline: none;
+}
+
+[data-listbox][data-block] {
+	display: flex;
+	inline-size: 100%;
+}
+
+[data-listbox][data-orientation='horizontal'] {
+	flex-direction: row;
+	flex-wrap: wrap;
+	align-items: center;
+}
+
+/* ── Variant — surface (default) ─ */
+[data-listbox][data-variant='surface'] {
+	background: var(--color-surface-default);
+	border-color: var(--color-border-default);
+}
+
+[data-listbox][data-variant='outline'] {
+	background: transparent;
+	border-color: var(--color-border-default);
+}
+
+[data-listbox][data-variant='ghost'] {
+	background: transparent;
+	border-color: transparent;
+}
+
+/* ── Sizes ─ */
+[data-listbox][data-size='xs'] {
+	--_listbox-item-height: var(--control-height-xs);
+	--_listbox-item-px: var(--space-2);
+	--_listbox-item-font-size: var(--font-size-xs);
+}
+
+[data-listbox][data-size='sm'] {
+	--_listbox-item-height: var(--control-height-sm);
+	--_listbox-item-px: var(--space-2);
+	--_listbox-item-font-size: var(--font-size-sm);
+}
+
+[data-listbox][data-size='lg'] {
+	--_listbox-item-height: var(--control-height-lg);
+	--_listbox-item-px: var(--space-4);
+	--_listbox-item-font-size: var(--font-size-md);
+}
+
+[data-listbox][data-size='xl'] {
+	--_listbox-item-height: var(--control-height-xl);
+	--_listbox-item-px: var(--space-5);
+	--_listbox-item-font-size: var(--font-size-lg);
+}
+
+/* ── Color cascades ─ */
+[data-listbox][data-color='secondary'] {
+	--_listbox-accent: var(--color-secondary-solid);
+	--_listbox-accent-soft: var(--color-secondary-element);
+}
+[data-listbox][data-color='affirm'] {
+	--_listbox-accent: var(--color-affirm-solid);
+	--_listbox-accent-soft: var(--color-affirm-element);
+}
+[data-listbox][data-color='risk'] {
+	--_listbox-accent: var(--color-risk-solid);
+	--_listbox-accent-soft: var(--color-risk-element);
+}
+[data-listbox][data-color='threat'] {
+	--_listbox-accent: var(--color-threat-solid);
+	--_listbox-accent-soft: var(--color-threat-element);
+}
+[data-listbox][data-color='fulfill'] {
+	--_listbox-accent: var(--color-fulfill-solid);
+	--_listbox-accent-soft: var(--color-fulfill-element);
+}
+[data-listbox][data-color='loss'] {
+	--_listbox-accent: var(--color-loss-solid);
+	--_listbox-accent-soft: var(--color-loss-element);
+}
+[data-listbox][data-color='neutral'] {
+	--_listbox-accent: var(--color-neutral-solid);
+	--_listbox-accent-soft: var(--color-neutral-element);
+}
+
+[data-listbox][data-disabled] {
+	opacity: 0.55;
+	cursor: not-allowed;
+}
+
+[data-listbox][data-invalid] {
+	border-color: var(--color-threat-element);
+}
+
+[data-listbox]:focus-visible,
+[data-listbox][data-focused] {
+	outline: var(--focus-ring-width) solid var(--focus-ring-color);
+	outline-offset: var(--focus-ring-offset);
+}
+
+/* ── Item ─ */
+[data-listbox-item] {
+	display: flex;
+	align-items: center;
+	gap: var(--space-2);
+	min-block-size: var(--_listbox-item-height);
+	padding-block: var(--space-1);
+	padding-inline: var(--_listbox-item-px);
+	border-radius: var(--radius-sm);
+	color: var(--color-content-primary);
+	cursor: pointer;
+	user-select: none;
+	transition:
+		background var(--duration-fast) var(--ease-default),
+		color var(--duration-fast) var(--ease-default);
+}
+
+[data-listbox-item][data-highlighted]:not([data-disabled]) {
+	background: var(--color-surface-overlay);
+}
+
+[data-listbox-item][data-selected]:not([data-disabled]) {
+	background: var(--_listbox-accent-soft);
+	color: var(--color-content-primary);
+}
+
+[data-listbox-item][data-selected][data-highlighted]:not([data-disabled]) {
+	background: var(--_listbox-accent-soft);
+}
+
+[data-listbox-item][data-disabled] {
+	color: var(--color-content-muted);
+	cursor: default;
+	opacity: 0.6;
+}
+
+/* ── ItemIndicator (✓ glyph on selected items) ─
+ *
+ * Painted as a 0.875rem filled-accent rounded square with white check —
+ * same shape as the menu-indicator partial used by Dropdown/Context
+ * Menu CheckboxItems. The ItemIndicator is rendered by the consumer
+ * (soma emits the data-attr; visibility is gated to selected).
+ */
+[data-listbox-item-indicator] {
+	display: none;
+	inline-size: 0.875rem;
+	block-size: 0.875rem;
+	flex: 0 0 auto;
+	color: var(--_listbox-accent);
+}
+
+[data-listbox-item][data-selected] [data-listbox-item-indicator] {
+	display: inline-flex;
+	align-items: center;
+	justify-content: center;
+}
+
+/* ── Group / GroupLabel ─ */
+[data-listbox-group] {
+	display: flex;
+	flex-direction: column;
+	gap: var(--space-1);
+}
+
+[data-listbox-group-label] {
+	padding-block: var(--space-1);
+	padding-inline: var(--_listbox-item-px);
+	color: var(--color-content-muted);
+	font-size: var(--font-size-xs);
+	font-weight: 500;
+	text-transform: uppercase;
+	letter-spacing: 0.04em;
+}

src/uix/eidos/components/listbox/listbox.svelte

@@ -0,0 +1,53 @@
+<script lang="ts">
+	/**
+	 * Eidos `<Listbox>` — visual wrapper over Soma's `<Listbox.Provider>`.
+	 *
+	 *   <Listbox bind:value selectionMode="single">
+	 *     <Listbox.Item value="apple">Apple</Listbox.Item>
+	 *     <Listbox.Item value="banana">Banana</Listbox.Item>
+	 *     <Listbox.Group>
+	 *       <Listbox.GroupLabel>Citrus</Listbox.GroupLabel>
+	 *       <Listbox.Item value="orange">Orange</Listbox.Item>
+	 *     </Listbox.Group>
+	 *   </Listbox>
+	 *
+	 * Soma owns single/multi selection, roving-tabindex keyboard nav
+	 * (Arrow / Home / End / typeahead / Ctrl+A), form participation,
+	 * Field integration. Eidos adds the visual surface (variant +
+	 * size + color) — Item rows reuse the option-row visuals shared
+	 * with Select / Combobox / Command.Item; ItemIndicator reuses the
+	 * menu-indicator partial (✓ glyph identical to standalone Checkbox).
+	 */
+	import { ActiveEidos } from '$uix/eidos';
+	import * as Listbox from '$soma/components/listbox';
+	import type { ListboxProps } from './types';
+
+	let {
+		size = 'md',
+		variant = 'surface',
+		color = 'primary',
+		block = false,
+		value = $bindable([] as string[]),
+		children: bodyContent,
+		...rest
+	}: ListboxProps = $props();
+
+	const eidos = ActiveEidos.require();
+	const resolvedSize = $derived(eidos.resolve(size, 'md'));
+	const resolvedVariant = $derived(eidos.resolve(variant, 'surface'));
+	const resolvedColor = $derived(eidos.resolve(color, 'primary'));
+	const resolvedBlock = $derived(eidos.resolve(block, false));
+</script>
+
+<Listbox.Provider
+	{...rest}
+	bind:value
+	data-size={resolvedSize}
+	data-variant={resolvedVariant}
+	data-color={resolvedColor}
+	data-block={resolvedBlock ? '' : undefined}
+>
+	{#snippet children(snippetProps)}
+		{@render bodyContent?.(snippetProps)}
+	{/snippet}
+</Listbox.Provider>

src/uix/eidos/components/listbox/types.ts

@@ -0,0 +1,42 @@
+import type { ColorRole, ControlVariant, ResponsiveProp, Size } from '$uix/eidos/lib/types';
+import type {
+	ProviderProps,
+	ItemProps,
+	ItemIndicatorProps,
+	GroupProps,
+	GroupLabelProps,
+	ProviderSnippetProps,
+	ItemSnippetProps,
+	ListboxSelectionMode
+} from '$soma/components/listbox';
+
+/**
+ * Listbox visual size — five-step subset matching the rest of the
+ * form-control family (Select, Combobox, Field, etc.).
+ */
+export type ListboxSize = Extract<Size, 'xs' | 'sm' | 'md' | 'lg' | 'xl'>;
+
+export type ListboxVariant = ControlVariant;
+export type ListboxColor = ColorRole;
+
+export type ListboxProps = ProviderProps & {
+	/** Visual size — drives item height + font-size. @default 'md' */
+	size?: ResponsiveProp<ListboxSize>;
+	/** Container chrome variant. @default 'surface' */
+	variant?: ListboxVariant;
+	/** Accent palette for selected items + focus ring. @default 'primary' */
+	color?: ListboxColor;
+	/** Stretch to fill the container's inline-size. @default false */
+	block?: boolean;
+};
+
+export type ListboxItemProps = ItemProps;
+export type ListboxItemIndicatorProps = ItemIndicatorProps;
+export type ListboxGroupProps = GroupProps;
+export type ListboxGroupLabelProps = GroupLabelProps;
+
+export type {
+	ProviderSnippetProps as ListboxProviderSnippetProps,
+	ItemSnippetProps as ListboxItemSnippetProps,
+	ListboxSelectionMode
+};

src/uix/eidos/index.css

@@ -96,6 +96,7 @@
 @import './components/context-menu/context-menu.css';
 @import './components/menubar/menubar.css';
 @import './components/command/command.css';
+@import './components/listbox/listbox.css';
 /* Shared menu-item indicator partial — must load AFTER the menu recipes
    so its `padding-inline-start` calc wins over the row rule's
    `padding-inline` shorthand at equal specificity. */

web/routes/uix/+layout@.svelte

@@ -148,6 +148,7 @@
 				{ slug: '/uix/components/search-field', label: 'Search field' },
 				{ slug: '/uix/components/select', label: 'Select' },
 				{ slug: '/uix/components/combobox', label: 'Combobox' },
+				{ slug: '/uix/components/listbox', label: 'Listbox' },
 				{ slug: '/uix/components/calendar', label: 'Calendar' },
 				{ slug: '/uix/components/month-grid', label: 'Month grid' },
 				{ slug: '/uix/components/year-grid', label: 'Year grid' },

web/routes/uix/components/listbox/+page.svelte

@@ -0,0 +1,601 @@
+<script lang="ts">
+	import {
+		Listbox,
+		type ListboxSize,
+		type ListboxVariant,
+		type ListboxColor,
+		type ListboxSelectionMode
+	} from '$uix/eidos/components/listbox';
+	import { compileMorfo } from '$uix/morfo';
+	import { listboxMorfo } from '@/uix/morfo/components/listbox';
+	import { getActiveUix } from '$active-uix';
+
+	const uix = getActiveUix();
+
+	type Tab = 'live' | 'api' | 'morfo' | 'sema' | 'recipe' | 'a11y';
+	let tab = $state<Tab>('live');
+
+	// ── Live state ────────────────────────────────────────────────────────
+	let value = $state<string[]>(['banana']);
+	let selectionMode = $state<ListboxSelectionMode>('single');
+	let size = $state<ListboxSize>('md');
+	let variant = $state<ListboxVariant>('surface');
+	let color = $state<ListboxColor>('primary');
+	let orientation = $state<'vertical' | 'horizontal'>('vertical');
+	let loop = $state(true);
+	let typeahead = $state(true);
+	let disabled = $state(false);
+	let invalid = $state(false);
+	let block = $state(false);
+
+	type TraceEntry = { event: string; family: string; intent?: string; at: number };
+	let trace = $state<TraceEntry[]>([]);
+	let stageRef = $state<HTMLElement | null>(null);
+
+	$effect(() => {
+		const el = stageRef;
+		if (!el) return;
+		const obs = new MutationObserver((mutations) => {
+			for (const m of mutations) {
+				if (m.attributeName !== 'data-event') continue;
+				const target = m.target as Element;
+				const ev = target.getAttribute('data-event');
+				if (!ev) continue;
+				trace = [
+					{
+						event: ev,
+						family: target.getAttribute('data-event-family') ?? '—',
+						intent: target.getAttribute('data-event-intent') ?? undefined,
+						at: Date.now()
+					},
+					...trace
+				].slice(0, 6);
+			}
+		});
+		obs.observe(el, { attributes: true, subtree: true, attributeFilter: ['data-event'] });
+		return () => obs.disconnect();
+	});
+
+	const compiled = compileMorfo(listboxMorfo);
+	const partsList = $derived([...compiled.parts.byKebab.values()]);
+	const events = $derived([...compiled.actions.byName.values()]);
+
+	function fmtTime(at: number): string {
+		const d = new Date(at);
+		return `${String(d.getSeconds()).padStart(2, '0')}.${String(d.getMilliseconds()).padStart(3, '0')}`;
+	}
+
+	const somaSnippet = $derived(
+		[
+			"<script lang='ts'>",
+			"  import * as Listbox from '$soma/components/listbox';",
+			'  let value = $state<string[]>([]);',
+			'</' + 'script>',
+			'',
+			'<Listbox.Provider',
+			'  bind:value',
+			selectionMode !== 'single' && `  selectionMode="${selectionMode}"`,
+			orientation !== 'vertical' && `  orientation="${orientation}"`,
+			!loop && '  loop={false}',
+			!typeahead && '  typeahead={false}',
+			disabled && '  disabled',
+			invalid && '  invalid',
+			'>',
+			'  <Listbox.Item value="apple">Apple</Listbox.Item>',
+			'  <Listbox.Item value="banana">Banana</Listbox.Item>',
+			'  <Listbox.Item value="cherry" disabled>Cherry</Listbox.Item>',
+			'</Listbox.Provider>'
+		]
+			.filter(Boolean)
+			.join('\n')
+	);
+
+	const eidosSnippet = $derived(
+		[
+			"<script lang='ts'>",
+			"  import { Listbox } from '$uix/eidos/components/listbox';",
+			'  let value = $state<string[]>([]);',
+			'</' + 'script>',
+			'',
+			'<Listbox',
+			'  bind:value',
+			selectionMode !== 'single' && `  selectionMode="${selectionMode}"`,
+			size !== 'md' && `  size="${size}"`,
+			variant !== 'surface' && `  variant="${variant}"`,
+			color !== 'primary' && `  color="${color}"`,
+			orientation !== 'vertical' && `  orientation="${orientation}"`,
+			!loop && '  loop={false}',
+			block && '  block',
+			disabled && '  disabled',
+			invalid && '  invalid',
+			'>',
+			'  <Listbox.Item value="apple">',
+			'    <Listbox.ItemIndicator />',
+			'    Apple',
+			'  </Listbox.Item>',
+			'  <Listbox.Item value="banana">',
+			'    <Listbox.ItemIndicator />',
+			'    Banana',
+			'  </Listbox.Item>',
+			'  <Listbox.Group>',
+			'    <Listbox.GroupLabel>Citrus</Listbox.GroupLabel>',
+			'    <Listbox.Item value="orange">Orange</Listbox.Item>',
+			'  </Listbox.Group>',
+			'</Listbox>'
+		]
+			.filter(Boolean)
+			.join('\n')
+	);
+</script>
+
+<div data-uix-canvas-inner>
+	<header>
+		<div data-uix-eyebrow>Forms · Listbox</div>
+		<h1 data-uix-page-title>Listbox</h1>
+		<p data-uix-page-lede>
+			Embedded selection list (<code>role="listbox"</code>) with single
+			or multiple selection, roving-tabindex keyboard nav, alphanumeric
+			typeahead, ARIA-grouped sections, and form participation. Soma
+			OR-merges <code>disabled</code> / <code>readonly</code> /
+			<code>required</code> / <code>invalid</code> with
+			<code>Field.Provider</code> when nested. For atomic options
+			only — use <code>GridList</code> when rows contain interactive
+			children, or <code>Select</code> / <code>Combobox</code> when
+			the surface is a closed combobox-style picker.
+		</p>
+		<div data-uix-page-meta>
+			<span data-uix-meta-pill>
+				<span data-uix-meta-key>parts</span>{compiled.parts.order.length}
+			</span>
+			<span data-uix-meta-pill>
+				<span data-uix-meta-key>events</span>{events.length}
+			</span>
+			<span data-uix-meta-pill>
+				<span data-uix-meta-key>sizes</span>5
+			</span>
+			<span data-uix-meta-pill>
+				<span data-uix-meta-key>apg</span>
+				<a href={listboxMorfo.apg} target="_blank" rel="noreferrer">listbox ↗</a>
+			</span>
+			<span data-uix-meta-pill>
+				<span data-uix-meta-key>selected</span> {value.join(', ') || '—'}
+			</span>
+		</div>
+	</header>
+
+	<div data-uix-stage>
+		<div data-uix-stage-area bind:this={stageRef} style="min-block-size: 14rem; padding: var(--uix-space-3); display: flex; justify-content: center;">
+			<div style="inline-size: min(20rem, 100%);">
+				<Listbox
+					bind:value
+					{selectionMode}
+					{size}
+					{variant}
+					{color}
+					{orientation}
+					{loop}
+					{typeahead}
+					{disabled}
+					{invalid}
+					{block}
+				>
+					<Listbox.Item value="apple">
+						<Listbox.ItemIndicator />
+						Apple
+					</Listbox.Item>
+					<Listbox.Item value="banana">
+						<Listbox.ItemIndicator />
+						Banana
+					</Listbox.Item>
+					<Listbox.Item value="cherry" disabled>
+						<Listbox.ItemIndicator />
+						Cherry (disabled)
+					</Listbox.Item>
+					<Listbox.Group>
+						<Listbox.GroupLabel>Citrus</Listbox.GroupLabel>
+						<Listbox.Item value="orange">
+							<Listbox.ItemIndicator />
+							Orange
+						</Listbox.Item>
+						<Listbox.Item value="lemon">
+							<Listbox.ItemIndicator />
+							Lemon
+						</Listbox.Item>
+						<Listbox.Item value="grapefruit">
+							<Listbox.ItemIndicator />
+							Grapefruit
+						</Listbox.Item>
+					</Listbox.Group>
+					<Listbox.Group>
+						<Listbox.GroupLabel>Berries</Listbox.GroupLabel>
+						<Listbox.Item value="strawberry">
+							<Listbox.ItemIndicator />
+							Strawberry
+						</Listbox.Item>
+						<Listbox.Item value="blueberry">
+							<Listbox.ItemIndicator />
+							Blueberry
+						</Listbox.Item>
+					</Listbox.Group>
+				</Listbox>
+			</div>
+		</div>
+		<div data-uix-stage-trace>
+			<span data-uix-stage-trace-key>trace</span>
+			{#if trace.length === 0}
+				<span>focus the listbox + arrow / type to highlight</span>
+			{:else}
+				{#each trace.slice(0, 3) as entry (entry.at)}
+					<span><span data-uix-stage-trace-event>{entry.event}</span> · {entry.family}{entry.intent ? ' · ' + entry.intent : ''}</span>
+					<span style="color: var(--uix-text-faint)">{fmtTime(entry.at)}</span>
+				{/each}
+			{/if}
+			<span style="margin-inline-start: auto;">
+				<span data-uix-stage-trace-key>value</span> [{value.join(', ')}]
+			</span>
+		</div>
+	</div>
+
+	<div data-uix-tabs role="tablist">
+		<button data-uix-tab data-active={tab === 'live'} onclick={() => (tab = 'live')}>Live</button>
+		<button data-uix-tab data-active={tab === 'api'} onclick={() => (tab = 'api')}>
+			API <span data-uix-tab-count>5</span>
+		</button>
+		<button data-uix-tab data-active={tab === 'morfo'} onclick={() => (tab = 'morfo')}>
+			<span data-uix-layer-badge="morfo">morfo</span>
+			<span data-uix-tab-count>{partsList.length}p · {events.length}e</span>
+		</button>
+		<button data-uix-tab data-active={tab === 'sema'} onclick={() => (tab = 'sema')}>
+			<span data-uix-layer-badge="sema">sema</span>
+			<span data-uix-tab-count>{events.length}</span>
+		</button>
+		<button data-uix-tab data-active={tab === 'recipe'} onclick={() => (tab = 'recipe')}>Recipe</button>
+		<button data-uix-tab data-active={tab === 'a11y'} onclick={() => (tab = 'a11y')}>A11y</button>
+	</div>
+
+	{#if tab === 'live'}
+		<section data-uix-section>
+			<h2 data-uix-section-title>Controls</h2>
+			<p data-uix-section-desc>
+				Soma owns selection + nav + typeahead. Eidos adds
+				<code>variant</code> / <code>size</code> / <code>color</code> chrome.
+			</p>
+
+			<div data-uix-subsection-head>
+				<span data-uix-layer-badge="soma">soma</span> Provider props
+			</div>
+			<div data-uix-controls>
+				<label data-uix-control>
+					<span data-uix-control-label>selectionMode</span>
+					<span data-uix-chips role="radiogroup">
+						{#each ['single', 'multiple'] as m (m)}
+							<button data-uix-chip data-active={selectionMode === m} onclick={() => (selectionMode = m as ListboxSelectionMode)}>{m}</button>
+						{/each}
+					</span>
+				</label>
+				<label data-uix-control>
+					<span data-uix-control-label>orientation</span>
+					<span data-uix-chips role="radiogroup">
+						{#each ['vertical', 'horizontal'] as o (o)}
+							<button data-uix-chip data-active={orientation === o} onclick={() => (orientation = o as typeof orientation)}>{o}</button>
+						{/each}
+					</span>
+				</label>
+				<label data-uix-control>
+					<span data-uix-control-label>loop</span>
+					<span data-uix-switch>
+						<input type="checkbox" bind:checked={loop} />
+						<span data-uix-switch-label>{loop ? 'on' : 'off'}</span>
+					</span>
+				</label>
+				<label data-uix-control>
+					<span data-uix-control-label>typeahead</span>
+					<span data-uix-switch>
+						<input type="checkbox" bind:checked={typeahead} />
+						<span data-uix-switch-label>{typeahead ? 'on' : 'off'}</span>
+					</span>
+				</label>
+				<label data-uix-control>
+					<span data-uix-control-label>disabled</span>
+					<span data-uix-switch>
+						<input type="checkbox" bind:checked={disabled} />
+						<span data-uix-switch-label>{disabled ? 'on' : 'off'}</span>
+					</span>
+				</label>
+				<label data-uix-control>
+					<span data-uix-control-label>invalid</span>
+					<span data-uix-switch>
+						<input type="checkbox" bind:checked={invalid} />
+						<span data-uix-switch-label>{invalid ? 'on' : 'off'}</span>
+					</span>
+				</label>
+			</div>
+
+			<div data-uix-subsection-head>
+				<span data-uix-layer-badge="eidos">eidos</span> visual props
+			</div>
+			<div data-uix-controls>
+				<label data-uix-control>
+					<span data-uix-control-label>variant <span data-uix-control-hint>ControlVariant</span></span>
+					<span data-uix-chips role="radiogroup">
+						{#each ['surface', 'outline', 'ghost'] as v (v)}
+							<button data-uix-chip data-active={variant === v} onclick={() => (variant = v as ListboxVariant)}>{v}</button>
+						{/each}
+					</span>
+				</label>
+				<label data-uix-control>
+					<span data-uix-control-label>size</span>
+					<span data-uix-chips role="radiogroup">
+						{#each ['xs', 'sm', 'md', 'lg', 'xl'] as s (s)}
+							<button data-uix-chip data-active={size === s} onclick={() => (size = s as ListboxSize)}>{s}</button>
+						{/each}
+					</span>
+				</label>
+				<label data-uix-control>
+					<span data-uix-control-label>color</span>
+					<span data-uix-chips role="radiogroup">
+						{#each ['primary', 'secondary', 'neutral', 'affirm', 'fulfill', 'risk', 'threat', 'loss'] as c (c)}
+							<button data-uix-chip data-active={color === c} onclick={() => (color = c as ListboxColor)}>{c}</button>
+						{/each}
+					</span>
+				</label>
+				<label data-uix-control>
+					<span data-uix-control-label>block</span>
+					<span data-uix-switch>
+						<input type="checkbox" bind:checked={block} />
+						<span data-uix-switch-label>{block ? 'on' : 'off'}</span>
+					</span>
+				</label>
+			</div>
+
+			<div data-uix-code>
+				<div data-uix-code-head>
+					<span data-uix-layer-badge="soma">soma</span>
+					<span>headless · selection + keyboard + Field merge</span>
+					<span data-uix-code-lang>svelte</span>
+				</div>
+				<pre><code>{somaSnippet}</code></pre>
+			</div>
+
+			<div data-uix-code style="margin-top: var(--uix-space-3);">
+				<div data-uix-code-head>
+					<span data-uix-layer-badge="eidos">eidos</span>
+					<span>visual · variant + size + color</span>
+					<span data-uix-code-lang>svelte</span>
+				</div>
+				<pre><code>{eidosSnippet}</code></pre>
+			</div>
+		</section>
+	{/if}
+
+	{#if tab === 'api'}
+		<section data-uix-section>
+			<h2 data-uix-section-title>API reference</h2>
+			<p data-uix-section-desc>5 parts: Root, Item, ItemIndicator, Group, GroupLabel.</p>
+
+			<div data-uix-subsection-head>Root (Listbox)</div>
+			<div data-uix-table-wrap>
+				<table data-uix-table>
+					<thead><tr><th>Prop</th><th>Type</th><th>Default</th><th>Description</th></tr></thead>
+					<tbody>
+						<tr><td class="name">value <span data-uix-tag data-kind="bindable">bindable</span></td><td class="type">string[]</td><td class="default">[]</td><td>Current selection. Always string[]; single mode keeps at most one entry.</td></tr>
+						<tr><td class="name">selectionMode</td><td class="type">'single' | 'multiple'</td><td class="default">'single'</td><td>Selection behavior.</td></tr>
+						<tr><td class="name">loop</td><td class="type">boolean</td><td class="default">true</td><td>Wrap arrow nav at edges.</td></tr>
+						<tr><td class="name">typeahead</td><td class="type">boolean</td><td class="default">true</td><td>Alphanumeric jump-to-item.</td></tr>
+						<tr><td class="name">orientation</td><td class="type">'vertical' | 'horizontal'</td><td class="default">'vertical'</td><td>Arrow nav axis.</td></tr>
+						<tr><td class="name">disabled · readonly · required · invalid</td><td class="type">boolean</td><td class="default">false</td><td>OR-merged with Field.Provider when nested.</td></tr>
+						<tr><td class="name">name</td><td class="type">string</td><td class="default empty">—</td><td>Form name → hidden inputs per selected value.</td></tr>
+						<tr><td class="name">variant <span data-uix-tag data-kind="eidos">eidos</span></td><td class="type">ControlVariant: 'surface' | 'outline' | 'ghost'</td><td class="default">'surface'</td><td>Container chrome.</td></tr>
+						<tr><td class="name">size <span data-uix-tag data-kind="eidos">eidos</span></td><td class="type">'xs' | 'sm' | 'md' | 'lg' | 'xl'</td><td class="default">'md'</td><td>Item height + font-size.</td></tr>
+						<tr><td class="name">color <span data-uix-tag data-kind="eidos">eidos</span></td><td class="type">ColorRole</td><td class="default">'primary'</td><td>Selected-item highlight + focus ring accent.</td></tr>
+						<tr><td class="name">block <span data-uix-tag data-kind="eidos">eidos</span></td><td class="type">boolean</td><td class="default">false</td><td>Fill container's inline-size.</td></tr>
+					</tbody>
+				</table>
+			</div>
+
+			<div data-uix-subsection-head>Item</div>
+			<div data-uix-table-wrap>
+				<table data-uix-table>
+					<thead><tr><th>Prop</th><th>Type</th><th>Default</th><th>Description</th></tr></thead>
+					<tbody>
+						<tr><td class="name">value</td><td class="type">string</td><td class="default empty">required</td><td>Unique identifier in the listbox.</td></tr>
+						<tr><td class="name">disabled</td><td class="type">boolean</td><td class="default">false</td><td>Skip the item from keyboard nav + click selection.</td></tr>
+					</tbody>
+				</table>
+			</div>
+
+			<div data-uix-subsection-head>ItemIndicator · Group · GroupLabel</div>
+			<p data-uix-section-desc style="margin-top: 0.25rem;">
+				<code>ItemIndicator</code> renders a ✓ glyph inside selected items
+				(same recipe as menu-indicator partial). <code>Group</code> wraps a
+				logical section; <code>GroupLabel</code> is the muted heading
+				(ARIA-linked via <code>aria-labelledby</code>).
+			</p>
+		</section>
+	{/if}
+
+	{#if tab === 'morfo'}
+		<section data-uix-section>
+			<h2 data-uix-section-title>
+				<span data-uix-layer-badge="morfo">morfo</span>
+				· declarative contract
+			</h2>
+			<p data-uix-section-desc>Source: <code>src/uix/morfo/components/listbox.ts</code>.</p>
+
+			<div data-uix-table-wrap>
+				<table data-uix-table>
+					<thead><tr><th>Field</th><th>Value</th></tr></thead>
+					<tbody>
+						<tr><td class="name">name</td><td class="type">"{listboxMorfo.name}"</td></tr>
+						<tr><td class="name">kebab</td><td class="type">"{listboxMorfo.kebab}"</td></tr>
+						<tr><td class="name">scope</td><td class="type">[{listboxMorfo.scope.map((s) => `"${s}"`).join(', ')}]</td></tr>
+						<tr><td class="name">apg</td><td><a href={listboxMorfo.apg} target="_blank" rel="noreferrer">{listboxMorfo.apg}</a></td></tr>
+						<tr><td class="name">parts.length</td><td class="default">{listboxMorfo.parts.length}</td></tr>
+						<tr><td class="name">events.length</td><td class="default">{events.length}</td></tr>
+					</tbody>
+				</table>
+			</div>
+
+			<div data-uix-subsection-head>Parts</div>
+			<div data-uix-table-wrap>
+				<table data-uix-table>
+					<thead><tr><th>Part</th><th>Marker</th><th>Element</th><th>Role</th><th>Archetype</th><th>States</th><th>Optional</th></tr></thead>
+					<tbody>
+						{#each partsList as part (part.kebab)}
+							<tr>
+								<td class="name">{part.kebab}</td>
+								<td><code data-uix-part-marker>[{part.marker}]</code></td>
+								<td class="type">&lt;{part.defaultElement}&gt;</td>
+								<td class="type">{part.role ?? '—'}</td>
+								<td class="default">{part.archetype ?? '—'}</td>
+								<td class="default">{part.states.length ? part.states.join(' | ') : '—'}</td>
+								<td class="default">{part.optional ? 'yes' : 'no'}</td>
+							</tr>
+						{/each}
+					</tbody>
+				</table>
+			</div>
+
+			<div data-uix-subsection-head>Events declaration</div>
+			<div data-uix-table-wrap>
+				<table data-uix-table>
+					<thead><tr><th>name</th><th>family</th><th>verb</th><th>sequence</th><th>intent</th><th>target</th></tr></thead>
+					<tbody>
+						{#each events as action (action.name)}
+							{@const sem = action.semantic}
+							{@const intentDecl = 'intent' in sem ? sem.intent : undefined}
+							{@const intentStr = typeof intentDecl === 'string' ? intentDecl : intentDecl ? `fromProp:${(intentDecl as { fromProp?: string }).fromProp ?? '?'}` : '—'}
+							<tr>
+								<td class="name">{action.name}</td>
+								<td class="type">{sem.family}</td>
+								<td>{sem.verb ?? '—'}</td>
+								<td>{sem.sequence ?? 'pre'}</td>
+								<td class="default">{intentStr}</td>
+								<td>{action.target}</td>
+							</tr>
+						{/each}
+					</tbody>
+				</table>
+			</div>
+		</section>
+	{/if}
+
+	{#if tab === 'sema'}
+		<section data-uix-section id="sema">
+			<h2 data-uix-section-title>
+				<span data-uix-layer-badge="sema">sema</span>
+				· events
+			</h2>
+			<p data-uix-section-desc>
+				Two events: <code>commit-select</code> (intent <code>affirm</code>)
+				when an item enters the selection; <code>commit-unselect</code>
+				(intent <code>neutral</code>) when it leaves.
+			</p>
+
+			<div data-uix-table-wrap>
+				<table data-uix-table>
+					<thead><tr><th>Name</th><th>Family</th><th>Verb</th><th>Sequence</th><th>Intent</th><th>Play</th></tr></thead>
+					<tbody>
+						{#each events as action (action.name)}
+							{@const intentDecl = 'intent' in action.semantic ? action.semantic.intent : undefined}
+							{@const effectiveIntent = typeof intentDecl === 'string' ? intentDecl : undefined}
+							<tr>
+								<td class="name">{action.name}</td>
+								<td class="type">{action.semantic.family}</td>
+								<td>{action.semantic.verb ?? '—'}</td>
+								<td>{action.semantic.sequence ?? 'pre'}</td>
+								<td class="default">{effectiveIntent ?? '—'}</td>
+								<td>
+									<button
+										data-uix-play
+										onclick={() => {
+											const target = (stageRef?.querySelector('[data-listbox-item]') ?? stageRef) as HTMLElement | null;
+											if (!target) return;
+											void uix.events?.emit({
+												name: action.name,
+												family: action.semantic.family,
+												target,
+												...(effectiveIntent ? { intent: effectiveIntent } : {})
+											});
+										}}
+									>▶ play</button>
+								</td>
+							</tr>
+						{/each}
+					</tbody>
+				</table>
+			</div>
+		</section>
+	{/if}
+
+	{#if tab === 'recipe'}
+		<section data-uix-section>
+			<h2 data-uix-section-title>Eidos recipe</h2>
+			<p data-uix-section-desc>Selectors at <code>src/uix/eidos/components/listbox/listbox.css</code>.</p>
+			<div data-uix-table-wrap>
+				<table data-uix-table>
+					<thead><tr><th>Selector</th><th>Source</th><th>What it paints</th></tr></thead>
+					<tbody>
+						<tr><td class="name">[data-listbox]</td><td><span data-uix-tag data-kind="eidos">eidos</span></td><td>Container — flex column, gap, border, padding.</td></tr>
+						<tr><td class="name">[data-listbox][data-size]</td><td><span data-uix-tag data-kind="eidos">eidos</span></td><td>Item height + font-size scale.</td></tr>
+						<tr><td class="name">[data-listbox][data-variant='outline' | 'ghost']</td><td><span data-uix-tag data-kind="eidos">eidos</span></td><td>Container chrome (border + bg).</td></tr>
+						<tr><td class="name">[data-listbox][data-color]</td><td><span data-uix-tag data-kind="eidos">eidos</span></td><td>Accent palette for selected highlight + focus ring.</td></tr>
+						<tr><td class="name">[data-listbox][data-invalid]</td><td><span data-uix-tag data-kind="soma">morfo</span></td><td>Threat-coloured border override.</td></tr>
+						<tr><td class="name">[data-listbox-item]</td><td><span data-uix-tag data-kind="soma">morfo</span></td><td>Option row — flex, padding, hover/highlight states.</td></tr>
+						<tr><td class="name">[data-listbox-item][data-selected]</td><td><span data-uix-tag data-kind="soma">morfo</span></td><td>Selected-state band (accent-soft fill).</td></tr>
+						<tr><td class="name">[data-listbox-item-indicator]</td><td><span data-uix-tag data-kind="soma">morfo</span></td><td>Hidden by default; revealed inside selected items.</td></tr>
+						<tr><td class="name">[data-listbox-group-label]</td><td><span data-uix-tag data-kind="soma">morfo</span></td><td>Muted uppercase section heading.</td></tr>
+					</tbody>
+				</table>
+			</div>
+		</section>
+	{/if}
+
+	{#if tab === 'a11y'}
+		<section data-uix-section>
+			<h2 data-uix-section-title>Accessibility</h2>
+			<p data-uix-section-desc>
+				Follows the APG <a href={listboxMorfo.apg} target="_blank" rel="noreferrer">listbox pattern</a>.
+				Container is <code>role="listbox"</code>; each Item is
+				<code>role="option"</code> with <code>aria-selected</code>;
+				Group is <code>role="group"</code> with
+				<code>aria-labelledby</code> pointing to GroupLabel.
+				<code>aria-multiselectable</code> is stamped automatically
+				in <code>multiple</code> mode.
+			</p>
+
+			<div data-uix-subsection-head>Keyboard</div>
+			<div data-uix-table-wrap>
+				<table data-uix-table>
+					<thead><tr><th>Key</th><th>Action</th></tr></thead>
+					<tbody>
+						<tr><td><span data-uix-kbd>ArrowDown</span> / <span data-uix-kbd>ArrowUp</span></td><td>Move highlight ±1 (vertical orientation).</td></tr>
+						<tr><td><span data-uix-kbd>ArrowRight</span> / <span data-uix-kbd>ArrowLeft</span></td><td>Same but for horizontal orientation; RTL inverts.</td></tr>
+						<tr><td><span data-uix-kbd>Home</span> / <span data-uix-kbd>End</span></td><td>First / last item.</td></tr>
+						<tr><td><span data-uix-kbd>Enter</span> / <span data-uix-kbd>Space</span></td><td>Toggle selection of highlighted item.</td></tr>
+						<tr><td><span data-uix-kbd>Ctrl/Cmd+A</span></td><td>Select all (multiple mode only).</td></tr>
+						<tr><td>Letter / digit</td><td>Typeahead — focus next item starting with that character.</td></tr>
+					</tbody>
+				</table>
+			</div>
+
+			<div data-uix-subsection-head>ARIA contract</div>
+			<div data-uix-table-wrap>
+				<table data-uix-table>
+					<thead><tr><th>Part</th><th>Attribute</th><th>Value</th></tr></thead>
+					<tbody>
+						<tr><td class="name">listbox</td><td>role</td><td class="type">"listbox"</td></tr>
+						<tr><td class="name">listbox</td><td>aria-multiselectable</td><td class="type">"true" (multiple mode)</td></tr>
+						<tr><td class="name">listbox</td><td>aria-orientation</td><td class="type">"horizontal" | "vertical"</td></tr>
+						<tr><td class="name">listbox</td><td>aria-disabled / aria-readonly / aria-required / aria-invalid</td><td class="type">flags</td></tr>
+						<tr><td class="name">item</td><td>role</td><td class="type">"option"</td></tr>
+						<tr><td class="name">item</td><td>aria-selected</td><td class="type">"true" | "false"</td></tr>
+						<tr><td class="name">item</td><td>aria-disabled</td><td class="type">"true" (disabled)</td></tr>
+						<tr><td class="name">group</td><td>role</td><td class="type">"group"</td></tr>
+						<tr><td class="name">group</td><td>aria-labelledby</td><td class="type">{`<group-label id>`}</td></tr>
+					</tbody>
+				</table>
+			</div>
+		</section>
+	{/if}
+</div>