✨ Implement LoadSwitchController for managing LoadSwitch widget state

Closes #5

Author: esentis

lib/src/load_switch_controller.dart

@@ -0,0 +1,87 @@
+import 'package:flutter/foundation.dart';
+
+/// Controller for managing the state of a [LoadSwitch] widget.
+///
+/// This controller allows for programmatic control of a [LoadSwitch] widget,
+/// including changing the value, loading state, and active state.
+class LoadSwitchController extends ChangeNotifier {
+  /// Creates a new [LoadSwitchController] with the specified initial values.
+  LoadSwitchController({
+    bool initialValue = false,
+    bool isLoading = false,
+    bool isActive = true,
+  })  : _value = initialValue,
+        _isLoading = isLoading,
+        _isActive = isActive;
+
+  bool _value;
+  bool _isLoading;
+  bool _isActive;
+
+  /// The current value of the switch (on/off).
+  bool get value => _value;
+
+  /// Whether the switch is currently in a loading state.
+  bool get isLoading => _isLoading;
+
+  /// Whether the switch is currently active and can be interacted with.
+  bool get isActive => _isActive;
+
+  /// Sets the value of the switch and notifies listeners.
+  set value(bool newValue) {
+    if (_value != newValue) {
+      _value = newValue;
+      notifyListeners();
+    }
+  }
+
+  /// Sets the loading state of the switch and notifies listeners.
+  set isLoading(bool loading) {
+    if (_isLoading != loading) {
+      _isLoading = loading;
+      notifyListeners();
+    }
+  }
+
+  /// Sets the active state of the switch and notifies listeners.
+  set isActive(bool active) {
+    if (_isActive != active) {
+      _isActive = active;
+      notifyListeners();
+    }
+  }
+
+  /// Toggles the value of the switch if it's not loading and is active.
+  void toggle() {
+    if (!_isLoading && _isActive) {
+      value = !value;
+    }
+  }
+
+  /// Executes a future with loading state management.
+  ///
+  /// Sets [isLoading] to true before executing the future, and to false after
+  /// the future completes or throws an error. Updates the value of the switch
+  /// based on the result of the future.
+  ///
+  /// If [onChange] is provided, it will be called with the new value.
+  /// If [onError] is provided, it will be called with any error that occurs.
+  Future<void> executeWithLoading(
+    Future<bool> Function() future, {
+    Function(bool)? onChange,
+    Function(Object)? onError,
+  }) async {
+    if (_isLoading || !_isActive) return;
+
+    isLoading = true;
+
+    try {
+      value = await future.call();
+      onChange?.call(value);
+    } catch (error) {
+      onError?.call(error);
+    } finally {
+      isLoading = false;
+    }
+  }
+}