fix(picker): ARIA combobox — listbox only when results; no tabindex on options

Status/error/empty messages rendered outside <ul role="listbox"> so the
element only contains role="option" children (fixes aria-required-children
axe violation). Options no longer carry tabindex or onkeydown — keyboard
navigation stays on the input per ARIA combobox pattern.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/lib/document/DocumentPickerDropdown.svelte

@@ -75,13 +75,6 @@ function handleKeydown(e: KeyboardEvent) {
 		picker.close();
 	}
 }
-
-function handleOptionKeydown(e: KeyboardEvent, doc: DocumentOption) {
-	if (e.key === 'Enter' || e.key === ' ') {
-		e.preventDefault();
-		handleSelect(doc);
-	}
-}
 </script>
 
 <div use:clickOutside onclickoutside={() => picker.close()} class="relative">
@@ -102,34 +95,45 @@ function handleOptionKeydown(e: KeyboardEvent, doc: DocumentOption) {
 	/>
 
 	{#if picker.isOpen}
-		<ul
+		{#if picker.loading}
-			id={listboxId}
+			<div
-			role="listbox"
+				class="ring-opacity-5 absolute z-50 mt-1 w-full rounded-md bg-surface py-1 text-sm shadow-lg ring-1 ring-black"
-			class="ring-opacity-5 absolute z-50 mt-1 max-h-60 w-full overflow-auto rounded-md bg-surface py-1 text-sm shadow-lg ring-1 ring-black"
+			>
-		>
+				<p role="status" class="px-3 py-2 text-ink-2">{m.comp_multiselect_loading()}</p>
-			{#if picker.loading}
+			</div>
-				<li class="px-3 py-2 text-ink-2">{m.comp_multiselect_loading()}</li>
+		{:else if picker.error}
-			{:else if picker.error}
+			<div
-				<li role="alert" class="px-3 py-2 text-danger">{m.comp_typeahead_error()}</li>
+				class="ring-opacity-5 absolute z-50 mt-1 w-full rounded-md bg-surface py-1 text-sm shadow-lg ring-1 ring-black"
-			{:else if picker.results.length === 0}
+			>
-				<li class="px-3 py-2 text-ink-2">{m.comp_typeahead_no_results()}</li>
+				<p role="alert" class="px-3 py-2 text-danger">{m.comp_typeahead_error()}</p>
-			{:else}
+			</div>
+		{:else if picker.results.length === 0}
+			<div
+				class="ring-opacity-5 absolute z-50 mt-1 w-full rounded-md bg-surface py-1 text-sm shadow-lg ring-1 ring-black"
+			>
+				<p role="status" class="px-3 py-2 text-ink-2">{m.comp_typeahead_no_results()}</p>
+			</div>
+		{:else}
+			<ul
+				id={listboxId}
+				role="listbox"
+				class="ring-opacity-5 absolute z-50 mt-1 max-h-60 w-full overflow-auto rounded-md bg-surface py-1 text-sm shadow-lg ring-1 ring-black"
+			>
 				{#each picker.results as doc, i (doc.id)}
 					{@const disabled = alreadyAddedIds.has(doc.id!)}
+					<!-- svelte-ignore a11y_click_events_have_key_events -->
 					<li
 						id={`${listboxId}-option-${i}`}
 						role="option"
 						aria-selected={i === picker.activeIndex}
 						aria-disabled={disabled}
 						onclick={() => handleSelect(doc)}
-						onkeydown={(e) => handleOptionKeydown(e, doc)}
-						tabindex={disabled ? -1 : 0}
 						class={[
 							'px-3 py-2 text-ink select-none',
 							i === picker.activeIndex ? 'bg-muted' : '',
 							disabled
 								? 'cursor-default opacity-50'
-								: 'cursor-pointer hover:bg-muted focus:bg-muted focus:outline-none'
+								: 'cursor-pointer hover:bg-muted'
 						].join(' ')}
 					>
 						{formatDocumentOption(doc)}
@@ -138,7 +142,7 @@ function handleOptionKeydown(e: KeyboardEvent, doc: DocumentOption) {
 						{/if}
 					</li>
 				{/each}
-			{/if}
+			</ul>
-		</ul>
+		{/if}
 	{/if}
 </div>

frontend/src/lib/document/DocumentPickerDropdown.svelte.spec.ts

@@ -198,3 +198,46 @@ describe('DocumentPickerDropdown — search failure', () => {
 		await expect.element(page.getByText(m.comp_typeahead_error())).toBeInTheDocument();
 	});
 });
+
+describe('DocumentPickerDropdown — ARIA listbox integrity', () => {
+	it('does not render a listbox when results are empty (no aria-required-children violation)', async () => {
+		mockSearchResponse([]);
+		render(DocumentPickerDropdown, { onSelect: vi.fn() });
+
+		await userEvent.fill(page.getByRole('combobox'), 'xyz');
+		await waitForDebounce();
+
+		// no-results message must be visible, but NOT inside a listbox
+		await expect.element(page.getByText(m.comp_typeahead_no_results())).toBeInTheDocument();
+		expect(document.querySelector('[role="listbox"]')).toBeNull();
+	});
+
+	it('does not render a listbox when loading (no aria-required-children violation)', async () => {
+		let resolveSearch!: (v: unknown) => void;
+		vi.stubGlobal(
+			'fetch',
+			vi.fn().mockReturnValue(new Promise((resolve) => (resolveSearch = resolve)))
+		);
+		render(DocumentPickerDropdown, { onSelect: vi.fn() });
+
+		await userEvent.fill(page.getByRole('combobox'), 'Brief');
+
+		// While in-flight, no listbox should exist
+		expect(document.querySelector('[role="listbox"]')).toBeNull();
+		resolveSearch({ ok: true, json: () => Promise.resolve({ items: [] }) });
+	});
+
+	it('option elements do not have tabindex (combobox pattern: focus stays on input)', async () => {
+		mockSearchResponse([docFactory('d1', 'Brief A'), docFactory('d2', 'Brief B')]);
+		render(DocumentPickerDropdown, { onSelect: vi.fn() });
+
+		await userEvent.fill(page.getByRole('combobox'), 'Brief');
+		await waitForDebounce();
+
+		const options = document.querySelectorAll('[role="listbox"] [role="option"]');
+		expect(options.length).toBeGreaterThan(0);
+		options.forEach((opt) => {
+			expect(opt).not.toHaveAttribute('tabindex');
+		});
+	});
+});