test(playwright): add playwright report to track changes + correct playwright parameters

ci: fix actions/checkout@v6 → @v4 (v6 does not exist)

GitHub started rejecting invalid action versions at parse time,
causing every CI run to fail with 0s / 'workflow file issue'
before any jobs could start.

 * test(e2e): only no retry
 * test(e2e): use static name in tests to facilitate screenshot comparaison
 * test(e2e): update linux screenshots
 * test(e2e): adapt test due to user-vignette generation

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

.gitignore

@@ -94,7 +94,6 @@ charts/*/charts/*
 # Playwright
 tests/e2e/node_modules/
 tests/e2e/test-results/
-tests/e2e/playwright-report/
 tests/e2e/blob-report/
 tests/e2e/playwright/.cache/
 tests/e2e/playwright/.auth/