test: cover five small index/empty-state route components

Three admin/index pages (groups/tags/users) — each renders a single
"Wähle X aus der Liste" prompt for the desktop split-view layout.
AuthHeader: brand link href + wordmark.
PersonsEmptyState: empty heading + explanation text.

6 tests across five small files.

Refs #496.

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

frontend/src/routes/AuthHeader.svelte.test.ts

@@ -0,0 +1,22 @@
+import { describe, it, expect, afterEach } from 'vitest';
+import { cleanup, render } from 'vitest-browser-svelte';
+import { page } from 'vitest/browser';
+import AuthHeader from './AuthHeader.svelte';
+
+afterEach(cleanup);
+
+describe('AuthHeader', () => {
+	it('renders the brand link to /', async () => {
+		render(AuthHeader, { props: {} });
+
+		await expect
+			.element(page.getByRole('link', { name: /familienarchiv/i }))
+			.toHaveAttribute('href', '/');
+	});
+
+	it('renders the brand wordmark', async () => {
+		render(AuthHeader, { props: {} });
+
+		await expect.element(page.getByText('Familienarchiv')).toBeVisible();
+	});
+});