(flutter) add const FlutterWebOptions

thermion_flutter/thermion_flutter/lib/thermion/widgets/thermion_widget_web_impl.dart

@@ -6,12 +6,12 @@ import 'package:web/web.dart';
 import 'package:flutter/widgets.dart';
 
 class ThermionWidgetWeb extends StatelessWidget {
+  final ThermionFlutterWebOptions options;
 
-  late final ThermionFlutterWebOptions options;
+  const ThermionWidgetWeb(
-
+      {super.key,
-  const ThermionWidgetWeb({super.key, ThermionFlutterWebOptions? options}) {
+      this.options =
-    this.options = options ?? ThermionFlutterWebOptions();
+          const ThermionFlutterWebOptions.empty()});
-  }
 
   @override
   Widget build(BuildContext context) {

thermion_flutter/thermion_flutter_web/lib/thermion_flutter_web_options.dart

@@ -1,8 +1,19 @@
 import 'package:thermion_flutter_platform_interface/thermion_flutter_platform_interface.dart';
 
 class ThermionFlutterWebOptions extends ThermionFlutterOptions {
-  bool createCanvas;
-  bool importCanvasAsWidget;
   
-  ThermionFlutterWebOptions({this.importCanvasAsWidget = false, this.createCanvas = true, String? uberarchivePath}) : super(uberarchivePath:uberarchivePath);
+  final bool createCanvas;
+  final bool importCanvasAsWidget;
+
+  ThermionFlutterWebOptions(
+      {this.importCanvasAsWidget = false,
+      this.createCanvas = true,
+      String? uberarchivePath})
+      : super(uberarchivePath: uberarchivePath);
+
+  const ThermionFlutterWebOptions.empty(
+      {this.importCanvasAsWidget = false,
+      this.createCanvas = true,
+      String? uberarchivePath})
+      : super.empty();
 }