Fix nightly E2E authentication fixture

[BorisTyshkevich]

Summary

• initialize the full-surface Dashboard E2E fixture through the app-owned authenticated execution lifecycle
• keep hover-revealed Dashboard row controls in the keyboard focus order
• make the cross-browser E2E assertion focus the direct action rather than assuming an engine-specific adjacent tab position

Root cause

The nightly scheduled browser run surfaced a fixture that replaced public execution-scope accessors, while renderApp() reads its private lifecycle state to decide whether the blocking authentication overlay starts hidden. The overlay therefore intercepted every Dashboard interaction. The same repair exposed that display: none controls could not be reached by keyboard in WebKit.

Validation

• npx playwright test tests/e2e/tile-open-workbench.spec.js (37 passed, 2 expected skips)
• npm test
• npm run build