feat(mobile): inline asset details (#25952)

The existing implementation for showing asset details uses a bottom
sheet, and is not in sync with the preview or scroll intent. Other apps
use inline details, which is much cleaner and feels better to use.

mobile/lib/extensions/scroll_extensions.dart

@@ -32,3 +32,125 @@ class FastClampingScrollPhysics extends ClampingScrollPhysics {
     damping: 80,
   );
 }
+
+class SnapScrollPhysics extends ScrollPhysics {
+  static const _minFlingVelocity = 700.0;
+  static const minSnapDistance = 30.0;
+
+  static final _spring = SpringDescription.withDampingRatio(mass: .5, stiffness: 300);
+
+  const SnapScrollPhysics({super.parent});
+
+  @override
+  SnapScrollPhysics applyTo(ScrollPhysics? ancestor) {
+    return SnapScrollPhysics(parent: buildParent(ancestor));
+  }
+
+  @override
+  Simulation? createBallisticSimulation(ScrollMetrics position, double velocity) {
+    assert(
+      position is SnapScrollPosition,
+      'SnapScrollPhysics can only be used with Scrollables that use a '
+      'controller whose createScrollPosition returns a SnapScrollPosition',
+    );
+
+    final snapOffset = (position as SnapScrollPosition).snapOffset;
+    if (snapOffset <= 0) {
+      return super.createBallisticSimulation(position, velocity);
+    }
+
+    if (position.pixels >= snapOffset) {
+      final simulation = super.createBallisticSimulation(position, velocity);
+      if (simulation == null || simulation.x(double.infinity) >= snapOffset) {
+        return simulation;
+      }
+    }
+
+    return ScrollSpringSimulation(
+      _spring,
+      position.pixels,
+      target(position, velocity, snapOffset),
+      velocity,
+      tolerance: toleranceFor(position),
+    );
+  }
+
+  static double target(ScrollMetrics position, double velocity, double snapOffset) {
+    if (velocity > _minFlingVelocity) return snapOffset;
+    if (velocity < -_minFlingVelocity) return position.pixels < snapOffset ? 0.0 : snapOffset;
+    return position.pixels < minSnapDistance ? 0.0 : snapOffset;
+  }
+}
+
+class SnapScrollPosition extends ScrollPositionWithSingleContext {
+  double snapOffset;
+
+  SnapScrollPosition({this.snapOffset = 0.0, required super.physics, required super.context, super.oldPosition});
+}
+
+class ProxyScrollController extends ScrollController {
+  final ScrollController scrollController;
+
+  ProxyScrollController({required this.scrollController});
+
+  SnapScrollPosition get snapPosition => position as SnapScrollPosition;
+
+  @override
+  ScrollPosition createScrollPosition(ScrollPhysics physics, ScrollContext context, ScrollPosition? oldPosition) {
+    return ProxyScrollPosition(
+      scrollController: scrollController,
+      physics: physics,
+      context: context,
+      oldPosition: oldPosition,
+    );
+  }
+
+  @override
+  void dispose() {
+    scrollController.dispose();
+    super.dispose();
+  }
+}
+
+class ProxyScrollPosition extends SnapScrollPosition {
+  final ScrollController scrollController;
+
+  ProxyScrollPosition({
+    required this.scrollController,
+    required super.physics,
+    required super.context,
+    super.oldPosition,
+  });
+
+  @override
+  double setPixels(double newPixels) {
+    final overscroll = super.setPixels(newPixels);
+    if (scrollController.hasClients && scrollController.position.pixels != pixels) {
+      scrollController.position.forcePixels(pixels);
+    }
+    return overscroll;
+  }
+
+  @override
+  void forcePixels(double value) {
+    super.forcePixels(value);
+    if (scrollController.hasClients && scrollController.position.pixels != pixels) {
+      scrollController.position.forcePixels(pixels);
+    }
+  }
+
+  @override
+  double get maxScrollExtent => scrollController.hasClients && scrollController.position.hasContentDimensions
+      ? scrollController.position.maxScrollExtent
+      : super.maxScrollExtent;
+
+  @override
+  double get minScrollExtent => scrollController.hasClients && scrollController.position.hasContentDimensions
+      ? scrollController.position.minScrollExtent
+      : super.minScrollExtent;
+
+  @override
+  double get viewportDimension => scrollController.hasClients && scrollController.position.hasViewportDimension
+      ? scrollController.position.viewportDimension
+      : super.viewportDimension;
+}