chore: Halkyon Todo's scaffold joins the repository in apps/todo

Its server, client and app as `serverpod create` made them, with the
switch to server-side sessions that was waiting uncommitted, as files:
its one commit holds the scaffold alone.

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/main.dart

@@ -0,0 +1,61 @@
+import 'package:flutter/material.dart';
+
+import 'client.dart';
+import 'screens/greetings_screen.dart';
+
+void main() async {
+  WidgetsFlutterBinding.ensureInitialized();
+  await initializeClient();
+  runApp(const MyApp());
+}
+
+/// Builds a theme for the given [brightness].
+ThemeData _buildTheme(Brightness brightness) {
+  return ThemeData(
+    colorScheme: ColorScheme.fromSeed(
+      seedColor: Colors.blue,
+      brightness: brightness,
+    ),
+  );
+}
+
+class MyApp extends StatelessWidget {
+  const MyApp({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: 'Serverpod Demo',
+      theme: _buildTheme(Brightness.light),
+      darkTheme: _buildTheme(Brightness.dark),
+      themeMode: ThemeMode.system,
+      home: const MyHomePage(title: 'Serverpod Example'),
+    );
+  }
+}
+
+class MyHomePage extends StatelessWidget {
+  const MyHomePage({super.key, required this.title});
+
+  final String title;
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(title: Text(title)),
+      body: const GreetingsScreen(),
+      // To test authentication in this example app, uncomment the line below
+      // and comment out the line above. This wraps the GreetingsScreen with a
+      // SignInScreen, which automatically shows a sign-in UI when the user is
+      // not authenticated and displays the GreetingsScreen once they sign in.
+      //
+      // body: SignInScreen(
+      //   child: GreetingsScreen(
+      //     onSignOut: () async {
+      //       await client.auth.signOutDevice();
+      //     },
+      //   ),
+      // ),
+    );
+  }
+}