update state

app/lib/features/geckoview/features/browser/presentation/widgets/draggable_scrollable_header.dart

@@ -37,8 +37,65 @@ class DraggableScrollableHeader extends StatefulWidget {
     super.key,
     required this.controller,
     required this.child,
+    this.velocitySensitivity = 0.25, // Higher = more sensitive to velocity
+    this.maxVelocity = 2500.0, // Maximum velocity to consider
+    this.minVelocity = 50.0, // Minimum velocity to trigger momentum
+    this.animationDuration = const Duration(milliseconds: 300),
+    this.animationCurve = Curves.decelerate,
+    this.dragSensitivity = 1.0, // Controls drag responsiveness
   });
 
+  @override
+  State<DraggableScrollableHeader> createState() =>
+      _DraggableScrollableHeaderState();
+}
+
+class _DraggableScrollableHeaderState extends State<DraggableScrollableHeader>
+    with TickerProviderStateMixin {
+  late AnimationController _animationController;
+  late Animation<double>? _animation;
+
+  @override
+  void initState() {
+    super.initState();
+    _animationController = AnimationController(
+      vsync: this,
+      duration: widget.animationDuration,
+    );
+  }
+
+  @override
+  void dispose() {
+    _animationController.dispose();
+    super.dispose();
+  }
+
+  Future<void> _animateToPosition(
+    double targetSize, {
+    Duration? customDuration,
+  }) async {
+    if (customDuration != null) {
+      _animationController.duration = customDuration;
+    } else {
+      _animationController.duration = widget.animationDuration;
+    }
+
+    _animation = Tween<double>(begin: widget.controller.size, end: targetSize)
+        .animate(
+          CurvedAnimation(
+            parent: _animationController,
+            curve: widget.animationCurve,
+          ),
+        );
+
+    _animationController.reset();
+    await _animationController.forward();
+
+    _animation!.addListener(() {
+      widget.controller.jumpTo(_animation!.value);
+    });
+  }
+
   @override
   Widget build(BuildContext context) {
     return GestureDetector(