The visualViewport ICB compensation (intended for Android ICB-stuck-large
and pinch-zoom) was also reacting to iOS soft-keyboard shrinkage, pushing
the mobile bottom nav up above the keyboard. Pass the existing
`keyboardOpen` prop through to a `mobile-nav-bar--keyboard-open` modifier
class that pins `bottom: 0` so the keyboard simply covers the bar.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>