feat: add StacVisibility widget

packages/stac/lib/src/framework/stac.dart

@@ -107,6 +107,7 @@ class Stac {
     const StacSetValueParser(),
     const StacInkwellParser(),
     const StacConditionalParser(),
+    const StacVisibilityParser(),
   ];
 
   static final _actionParsers = <StacActionParser>[

packages/stac/lib/src/parsers/widgets/stac_visibility/stac_visibility.dart

@@ -0,0 +1,23 @@
+import 'package:freezed_annotation/freezed_annotation.dart';
+
+export 'stac_visibility_parser.dart';
+
+part 'stac_visibility.freezed.dart';
+part 'stac_visibility.g.dart';
+
+@freezed
+abstract class StacVisibility with _$StacVisibility {
+  const factory StacVisibility({
+    required Map<String, dynamic> child,
+    bool? visible,
+    bool? maintainState,
+    bool? maintainAnimation,
+    bool? maintainSize,
+    bool? maintainSemantics,
+    bool? maintainInteractivity,
+    Map<String, dynamic>? replacement,
+  }) = _StacVisibility;
+
+  factory StacVisibility.fromJson(Map<String, dynamic> json) =>
+      _$StacVisibilityFromJson(json);
+}