fix(tests): fix 13 pre-existing vitest-browser spec failures

Fixes all remaining failing tests in the browser project. Root cause in
every case: Playwright CDP-based clicks/keyboard events do not reliably
trigger Svelte 5 onclick/onkeydown handlers. Pattern applied throughout:

- Buttons / result items: native `.element().click()` or
  `dispatchEvent(new MouseEvent('click', { bubbles: true }))`
- Keyboard events: `dispatchEvent(new KeyboardEvent('keydown', { key }))`
  on the target DOM element
- TipTap selection: `element.focus()` + Selection API +
  `document.dispatchEvent(new Event('selectionchange'))`
- ProseMirror focus for onFocus: `dispatchEvent(new FocusEvent('focus'))`

Also fixes pre-existing content/logic issues found during analysis:
- ChronikErrorCard, BulkDropZone, CorrespondenzHero: stale i18n strings
  and wrong ARIA role (combobox not textbox)
- RichtlinienRuleCard: beide beispielInput + beispielOutput required for
  arrow to render; querySelectorAll to get last code element
- admin/system/page: vi.unstubAllGlobals() in afterEach; strict-mode
  heading selector; per-call mockResolvedValueOnce for dual-card page
- DocumentList: add total prop + result count paragraph (test relied on it)
- PersonTypeahead keyboard navigation: pressKey() helper with native
  KeyboardEvent dispatch replaces userEvent.keyboard()
- PersonMultiSelect: native element clicks for result selection and
  chip removal; keydown dispatch on result div for Enter key test

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

frontend/src/routes/layout.svelte.spec.ts

@@ -1,11 +1,31 @@
-import { afterEach, describe, expect, it, vi } from 'vitest';
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 import { cleanup, render } from 'vitest-browser-svelte';
 import { page, userEvent } from 'vitest/browser';
 import { createRawSnippet } from 'svelte';
 
 vi.mock('$env/static/public', () => ({ PUBLIC_NOTIFICATION_POLL_MS: '60000' }));
 
-afterEach(cleanup);
+// NotificationBell calls notificationStore.init() on mount, which creates an
+// EventSource and immediately fetches the unread count.  In the test environment
+// the SSE connection fails (no backend), triggering onerror → another fetch.
+// If that fetch returns 401, notifications.svelte.ts calls
+// window.location.href = '/login', navigating the test iframe and breaking the
+// Playwright connection.  Stubbing fetch to return 200 keeps it in-check.
+beforeEach(() => {
+	vi.stubGlobal(
+		'fetch',
+		vi.fn().mockResolvedValue({
+			ok: true,
+			status: 200,
+			json: vi.fn().mockResolvedValue({ count: 0, content: [] })
+		})
+	);
+});
+
+afterEach(() => {
+	cleanup();
+	vi.unstubAllGlobals();
+});
 
 const emptySnippet = createRawSnippet(() => ({ render: () => '<span></span>' }));
 import Layout from './+layout.svelte';