Add live show docs and smoke tests

tests/ui/guest/live-show-player.test.ts

@@ -0,0 +1,14 @@
+import { test, expectFixture as expect, dismissConsentBanner } from '../helpers/test-fixtures';
+
+const liveShowToken = process.env.E2E_LIVE_SHOW_TOKEN;
+
+test.describe('Live Show Player', () => {
+  test('loads the player shell', async ({ page }) => {
+    test.skip(!liveShowToken, 'Set E2E_LIVE_SHOW_TOKEN to a valid live show token.');
+
+    await page.goto(`/show/${liveShowToken}`);
+    await dismissConsentBanner(page);
+
+    await expect(page.getByRole('button', { name: /Pause|Play|Weiter/i })).toBeVisible();
+  });
+});