feat(todo): the app on halkyon_app, with its own icon

Todo's app is halkyon_app's instance and session gates with Todo's
frame ("Todo" under "Halkyon", its icon, its own sentences) and an
instance check accepting only `todo`; TodoDependencies on an instance,
an empty TodoPerson per person, nothing kept or synced yet. A person
sees an empty home and their account: whose it is on which instance,
switching account, signing out and deleting it (each asking first where
it deletes), and About with the source of what the instance runs and
the licence list. Texts in British English and German. App ID
app.halkyon.todo on every platform, GitHub's callback scheme registered
on Android, no web build.

Its icon is Lucide's list-checks (lucide-static 1.50.0) in the brand's
blues on white: tool/app_icons.py draws its strokes with Pillow and
writes every platform's launcher icon; Lucide's ISC notice joins the
licence list.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

apps/todo/halkyon_todo_flutter/lib/driver.dart

@@ -1,14 +1,13 @@
-// This file is never meant to be used on real apps, just for development.
+// The app with the Flutter driver extension, as `serverpod start` launches it (the
+// server's pubspec, `flutter_apps`); never meant for real use, just development.
 // ignore: depend_on_referenced_packages
 import 'package:flutter_driver/driver_extension.dart';
-
-import 'main.dart' as app;
+import 'package:halkyon_todo_flutter/main.dart' as app;
 
 void main() {
   enableFlutterDriverExtension(
-    // Text entry emulation is disabled by default to allow manual usage of the
-    // app, but will be required for agents to type through the app. Set this
-    // parameter to true to switch from manual to automated usage.
+    // Off by default, so the app stays usable by hand; agents typing through
+    // the app set it to true.
     enableTextEntryEmulation: false,
   );
   app.main();