Replace fixed waits with waitForAngular in UI tests

The 3s waitForTimeout after page.goto wasn't enough for Angular to
bootstrap and render content. Replace with waitForAngular() helper
that waits for actual DOM elements (nav, headings) up to 15s, with
5s fallback.

32 calls updated across 10 test files.

Also adds waitForAngular to helpers.ts export.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/Web/StellaOps.Web/tests/e2e/integrations/gitlab-integration.e2e.spec.ts

@@ -18,6 +18,7 @@ import {
   createIntegrationViaApi,
   cleanupIntegrations,
   snap,
+  waitForAngular,
 } from './helpers';
 
 const BASE = process.env['PLAYWRIGHT_BASE_URL'] || 'https://stella-ops.local';
@@ -119,7 +120,7 @@ test.describe('GitLab Integration — UI Verification', () => {
         waitUntil: 'domcontentloaded',
         timeout: 45_000,
       });
-      await page.waitForTimeout(3_000);
+      await waitForAngular(page);
 
       const pageContent = await page.textContent('body');
       expect(pageContent).toContain('GitLab');