- main.tsx: on vite:preloadError (stale index.html referencing removed
hashed chunks after a redeploy) reload the page immediately.
- New ErrorBoundary around the whole router: render errors show a Persian
fallback with «تلاش مجدد» instead of wiping the DOM.
- nginx: index.html served with Cache-Control no-cache,no-store,
must-revalidate (verified live); /assets/* stays public, immutable.