refactor: action buttons and scroll to bottom ui/ux

lib/shared/widgets/measure_size.dart

@@ -0,0 +1,40 @@
+import 'package:flutter/rendering.dart';
+import 'package:flutter/widgets.dart';
+
+typedef OnWidgetSizeChange = void Function(Size size);
+
+class MeasureSize extends SingleChildRenderObjectWidget {
+  final OnWidgetSizeChange onChange;
+
+  const MeasureSize({super.key, required this.onChange, required Widget child})
+      : super(child: child);
+
+  @override
+  RenderObject createRenderObject(BuildContext context) {
+    return _MeasureSizeRenderObject(onChange);
+  }
+
+  @override
+  void updateRenderObject(
+      BuildContext context, covariant _MeasureSizeRenderObject renderObject) {
+    renderObject.onChange = onChange;
+  }
+}
+
+class _MeasureSizeRenderObject extends RenderProxyBox {
+  _MeasureSizeRenderObject(this.onChange);
+
+  OnWidgetSizeChange onChange;
+  Size? _oldSize;
+
+  @override
+  void performLayout() {
+    super.performLayout();
+    Size? newSize = child?.size;
+    if (_oldSize == newSize || newSize == null) return;
+    _oldSize = newSize;
+    WidgetsBinding.instance.addPostFrameCallback((_) {
+      onChange(newSize);
+    });
+  }
+}