test(briefwechsel): cover CorrespondenzHero branches

Headline + cross-link, recent-persons divider/chips visibility tied to
list length, onSelectPerson callback wiring, avatar initial uppercase
derivation.

5 tests, ~15 branches.

Refs #496.

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

frontend/src/routes/briefwechsel/CorrespondenzHero.svelte.test.ts

@@ -0,0 +1,67 @@
+import { describe, it, expect, vi, afterEach } from 'vitest';
+import { cleanup, render } from 'vitest-browser-svelte';
+import { page } from 'vitest/browser';
+import CorrespondenzHero from './CorrespondenzHero.svelte';
+
+afterEach(cleanup);
+
+describe('CorrespondenzHero', () => {
+	it('renders the headline and cross-link', async () => {
+		render(CorrespondenzHero, { props: { onSelectPerson: () => {} } });
+
+		await expect.element(page.getByRole('heading', { name: /wessen briefe/i })).toBeVisible();
+		await expect.element(page.getByRole('link', { name: /dokumentensuche/i })).toBeVisible();
+	});
+
+	it('omits the recent-persons section when recentPersons is empty', async () => {
+		render(CorrespondenzHero, { props: { onSelectPerson: () => {} } });
+
+		await expect.element(page.getByText('Zuletzt geöffnet')).not.toBeInTheDocument();
+	});
+
+	it('renders the recent-persons divider and chips when persons are provided', async () => {
+		render(CorrespondenzHero, {
+			props: {
+				onSelectPerson: () => {},
+				recentPersons: [
+					{ id: 'p1', name: 'Anna Schmidt' },
+					{ id: 'p2', name: 'Bert Meier' }
+				]
+			}
+		});
+
+		await expect.element(page.getByText('Zuletzt geöffnet')).toBeVisible();
+		await expect.element(page.getByText('Anna Schmidt')).toBeVisible();
+		await expect.element(page.getByText('Bert Meier')).toBeVisible();
+	});
+
+	it('calls onSelectPerson with the recent-person id when clicked', async () => {
+		const onSelectPerson = vi.fn();
+		render(CorrespondenzHero, {
+			props: {
+				onSelectPerson,
+				recentPersons: [{ id: 'p-42', name: 'Anna Schmidt' }]
+			}
+		});
+
+		const btn = document.querySelector('[data-testid="recent-person-p-42"]') as HTMLButtonElement;
+		btn.click();
+
+		expect(onSelectPerson).toHaveBeenCalledWith('p-42');
+	});
+
+	it('renders the avatar initial in the recent-person chip', async () => {
+		render(CorrespondenzHero, {
+			props: {
+				onSelectPerson: () => {},
+				recentPersons: [{ id: 'p1', name: 'anna schmidt' }]
+			}
+		});
+
+		// Avatar shows the uppercase first letter
+		const avatars = document.querySelectorAll(
+			'[data-testid^="recent-person-"] span[aria-hidden="true"]'
+		);
+		expect(avatars[0].textContent?.trim()).toBe('A');
+	});
+});