feat: refactor SDUI widget model to use sealed classes for type-safe handling, enhance form widget with stepper support, and improve error handling in SDUIFormWidget

packages/chicken/lib/presentation/widget/sdui/form/sdui_form_widget_controller.dart

@@ -0,0 +1,38 @@
+import 'package:rasadyar_core/core.dart';
+
+class SDUIFormWidgetController extends GetxController {
+  RxInt currentStep = 0.obs;
+  int totalSteps = 0;
+  String? stepperKey;
+
+  void initializeStepper(int totalSteps, String? key) {
+    this.totalSteps = totalSteps;
+    this.stepperKey = key;
+    currentStep.value = 0;
+  }
+
+  void nextStep(RxMap<String, dynamic>? state) {
+    if (currentStep.value < totalSteps - 1) {
+      currentStep.value++;
+      if (state != null && stepperKey != null) {
+        state[stepperKey!] = currentStep.value;
+      }
+    }
+  }
+
+  void previousStep(RxMap<String, dynamic>? state) {
+    if (currentStep.value > 0) {
+      currentStep.value--;
+      if (state != null && stepperKey != null) {
+        state[stepperKey!] = currentStep.value;
+      }
+    }
+  }
+
+  bool get canGoNext => currentStep.value < totalSteps - 1;
+  bool get canGoPrevious => currentStep.value > 0;
+  bool get isLastStep => currentStep.value == totalSteps - 1;
+}
+
+
+