Mobile browsers scroll the whole page up to show the focused input and do not
always scroll it back when the keyboard closes; the app never scrolls the page
itself, so the top bar (menu) stayed out of reach.
- Viewport interactive-widget=resizes-content: on Android the keyboard shrinks
the page instead of shifting it.
- Elsewhere (iOS Safari) the page offset is undone when the visual viewport
grows again or the input loses focus.
- The chat keeps following the latest message when its pane shrinks.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>