folder restructuring

lib/widget/centered_leading.dart

@@ -0,0 +1,13 @@
+import 'package:flutter/material.dart';
+
+class CenteredLeading extends StatelessWidget {
+  final Widget child;
+  const CenteredLeading(this.child, {super.key});
+
+  @override
+  Widget build(BuildContext context) => Column(
+      mainAxisAlignment: MainAxisAlignment.center,
+      crossAxisAlignment: CrossAxisAlignment.center,
+      children: [child],
+    );
+}