fix(e2e): fix Playwright E2E test suite for CI

- Replace __dirname with fileURLToPath(import.meta.url) for ESM compatibility
- Start SvelteKit dev server on port 3000 with 120s webServer timeout
- Add data-hydrated attribute (set in onMount) so tests wait for hydration
- Fix nav active class assertions: text-brand-navy (not border-brand-navy)
- Fix filter button selector: exact match to avoid matching "Alle Filter löschen"
- Fix date validation test: use pressSequentially('99') to trigger dateInvalid
- Fix person/document search: navigate directly to URL with query param
  (avoids debounced oninput → goto race condition in CI)
- Fix heading selector: level: 1 to avoid strict-mode with h1+h2 on page
- Fix auth redirect: return 401 from handleFetch instead of throwing redirect

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

frontend/e2e/auth.setup.ts

@@ -1,6 +1,8 @@
 import { test as setup } from '@playwright/test';
 import path from 'path';
+import { fileURLToPath } from 'url';
 
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
 const authFile = path.join(__dirname, '.auth/user.json');
 
 /**