Add touch scrolling on Linux

Workaround: on Linux, touch is recognized as mouse by Flutter,
so this enables scroll by dragging with mouse.

lib/main.dart

@@ -1,5 +1,8 @@
+import 'dart:io';
+
 import 'package:fluent_ui/fluent_ui.dart' as f;
 import 'package:flutter/cupertino.dart' as c;
+import 'package:flutter/gestures.dart';
 import 'package:flutter/material.dart' as m;
 import 'package:flutter/services.dart';
 import 'package:flutter/widgets.dart';
@@ -59,6 +62,36 @@ Map<String, WidgetBuilder> get routes => {
   },
 };
 
+class DragFluentScrollBevahior extends f.FluentScrollBehavior {
+  const DragFluentScrollBevahior();
+
+  @override
+  Set<PointerDeviceKind> get dragDevices => {
+    PointerDeviceKind.mouse,
+    PointerDeviceKind.touch,
+  };
+}
+
+class DragCupertinoScrollBevahior extends c.CupertinoScrollBehavior {
+  const DragCupertinoScrollBevahior();
+
+  @override
+  Set<PointerDeviceKind> get dragDevices => {
+    PointerDeviceKind.mouse,
+    PointerDeviceKind.touch,
+  };
+}
+
+class DragMaterialScrollBevahior extends m.MaterialScrollBehavior {
+  const DragMaterialScrollBevahior();
+
+  @override
+  Set<PointerDeviceKind> get dragDevices => {
+    PointerDeviceKind.mouse,
+    PointerDeviceKind.touch,
+  };
+}
+
 class StartPoint extends ConsumerWidget {
   final String appTitle = 'Info Tren';
 
@@ -83,6 +116,7 @@ class StartPoint extends ConsumerWidget {
             //   ),
             // ),
           ),
+          scrollBehavior: Platform.isLinux ? const DragCupertinoScrollBevahior() : null,
           routes: routes,
         ),
       );
@@ -95,6 +129,7 @@ class StartPoint extends ConsumerWidget {
           accentColor: f.Colors.blue,
         ),
         routes: routes,
+        scrollBehavior: Platform.isLinux ? const DragFluentScrollBevahior() : const f.FluentScrollBehavior(),
       );
     }
     else {
@@ -110,6 +145,7 @@ class StartPoint extends ConsumerWidget {
           useMaterial3: true,
           // fontFamily: 'Atkinson Hyperlegible',
         ),
+        scrollBehavior: Platform.isLinux ? const DragMaterialScrollBevahior() : null,
         routes: routes,
       );
     }