Android interactor assumes global positions which delays auto scrolling

[jellynoone]

Package Version
stable

To Reproduce
Steps to reproduce the behavior:

1. Run the example on Android (the bug affects Android handlers / interactor)
2. Scroll down to the end of the document
3. Long press on a word
4. Drag one of the extended handlers towards the top of the screen
5. Observe how the document only begins to auto-scroll after dragging over the app header

Minimal Reproduction Code

Minimal, Runnable Code Sample

import 'package:flutter/material.dart';
import 'package:super_editor/super_editor.dart';

void main() {
runApp(const MainApp());
}

class MainApp extends StatefulWidget {
const MainApp({super.key});

@override
State<MainApp> createState() => _MainAppState();
}

class _MainAppState extends State<MainApp> {
final _document = MutableDocument(nodes: [
  for (var i = 0; i < 40; i++)
    ParagraphNode(
      id: Editor.createNodeId(),
      text: AttributedText('Some random text. ' * (1 + i)),
    ),
]);
final _composer = MutableDocumentComposer();
late final _editor = createDefaultDocumentEditor(
  composer: _composer,
  document: _document,
);

@override
void dispose() {
  _editor.dispose();
  _document.dispose();
  _composer.dispose();
  super.dispose();
}

@override
Widget build(BuildContext context) {
  return MaterialApp(
    home: Scaffold(
      appBar: const PreferredSize(
        preferredSize: Size(double.infinity, 90),
        child: SafeArea(
          child: SizedBox(
            height: 90,
            child: ColoredBox(color: Colors.black),
          ),
        ),
      ),
      body: SuperEditor(
        editor: _editor,
        document: _document,
        composer: _composer,
      ),
    ),
  );
}
}

Actual behavior
Currently, on Android, autoscroll is only started after dragging the over the scaffold's header. On iOS, the autoscroll happens immediately at the boundary of the document.

Expected behavior
The auto-scroll should begin before the start of the document and not above it.
(It would also be nice to be able to control where the scroll start boundary is. It seems the bits are already there just not exposed through SuperEditor)

Platform
Android

Flutter version

Flutter 3.22.0 • channel stable • https://github.com/flutter/flutter.git
Framework • revision 5dcb86f68f (5 days ago) • 2024-05-09 07:39:20 -0500
Engine • revision f6344b75dc
Tools • Dart 3.4.0 • DevTools 2.34.3

Additional context
Originally, I wanted to adapt the example above to always use the Android gesture mode, however, it seems that setting gestureMode only effects selection styling. Popover toolbar and selection handlers are not displayed. It seems this is because SuperEditorAndroidHandlesDocumentLayerBuilder and other builders test for the defaultTargetPlatform to decide whether to build or not thus ignorring the gestureMode.