Documents the recommended approach for real-time dashboards that need to
poll server tools at regular intervals. Includes both Vanilla JS and
React examples with proper cleanup handling via `app.onteardown` and
`useEffect` cleanup functions respectively.
Also updates the "Tools that are private to Apps" section to mention
polling as a use case for app-only visibility.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>