shell library

Classes

AdaptiveScaffold
Adaptive navigation shell: a Material 3 NavigationBar on compact (phone) widths, and a NavigationRail on medium/expanded (tablet, desktop, web) widths. Also splits around a foldable's vertical hinge (a left/right fold) when one is reported, so the nav rail and content never straddle it. A horizontal hinge (a top/bottom fold) has no equivalent split for a side rail, so it falls back to the plain rail layout. https://docs.flutter.dev/ui/adaptive-responsive
AppGlobals
App-wide GlobalKeys and helpers for reaching navigation/snackbar state without a BuildContext in hand. Intentionally has no localization helper here — apps own their own AppLocalizations and should add a thin app-local getter on top of context.
Breakpoints
Window-size breakpoints per Material 3 adaptive guidance. https://docs.flutter.dev/ui/adaptive-responsive