Implemented new Stepper Button Widget

lib/widgets/stepper.dart

@@ -0,0 +1,73 @@
+import 'package:flutter/cupertino.dart'; // Für iOS-Style
+
+class Stepper extends StatefulWidget {
+  final int minValue;
+  final int maxValue;
+  final int? initialValue;
+  final int step;
+  final ValueChanged<int> onChanged;
+  const Stepper({
+    super.key,
+    required this.minValue,
+    required this.maxValue,
+    required this.step,
+    required this.onChanged,
+    this.initialValue,
+  });
+
+  @override
+  // ignore: library_private_types_in_public_api
+  _StepperState createState() => _StepperState();
+}
+
+class _StepperState extends State<Stepper> {
+  late int _value;
+
+  @override
+  void initState() {
+    super.initState();
+    final start = widget.initialValue ?? widget.minValue;
+    _value = start.clamp(widget.minValue, widget.maxValue);
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Row(
+      mainAxisSize: MainAxisSize.min,
+      children: [
+        CupertinoButton(
+          padding: const EdgeInsets.all(8),
+          onPressed: _decrement,
+          child: const Icon(CupertinoIcons.minus),
+        ),
+        Padding(
+          padding: const EdgeInsets.symmetric(horizontal: 12.0),
+          child: Text('$_value', style: const TextStyle(fontSize: 18)),
+        ),
+        CupertinoButton(
+          padding: const EdgeInsets.all(8),
+          onPressed: _increment,
+          child: const Icon(CupertinoIcons.add),
+        ),
+      ],
+    );
+  }
+
+  void _increment() {
+    if (_value + widget.step <= widget.maxValue) {
+      setState(() {
+        _value += widget.step;
+        widget.onChanged.call(_value);
+      });
+    }
+  }
+
+  void _decrement() {
+    if (_value - widget.step >= widget.minValue) {
+      setState(() {
+        _value -= widget.step;
+        widget.onChanged.call(_value);
+      });
+    }
+  }
+}