feat: add Flutter mobile clients and staff delivery API

apps/service_app/lib/main.dart

@@ -0,0 +1,10 @@
+import 'package:flutter/material.dart';
+
+import 'app/app.dart';
+import 'app/dependencies.dart';
+
+Future<void> main() async {
+  WidgetsFlutterBinding.ensureInitialized();
+  final dependencies = await AppDependencies.create();
+  runApp(ServiceClientApp(dependencies: dependencies));
+}