Load Flutter runtime config from Vault

lib/features/mapflow/presentation/mapflow_shell.dart

@@ -15,16 +15,17 @@ import '../../../app/router/app_router.dart';
 import '../../../app/theme/mapflow_theme.dart';
 import '../../../shared/auth/telegram_login_button.dart';
 import '../../../shared/auth/telegram_session.dart' as telegram_session;
+import '../../../shared/runtime_config/runtime_config.dart' as runtime_config;
 import '../application/place_cubit.dart';
 import '../data/auth_repository.dart';
 import '../data/places_repository.dart';
 import '../domain/place_models.dart';
 import 'widgets/place_photo_card.dart';
 
-const _mapboxStyle = String.fromEnvironment(
-  'MAPBOX_STYLE',
-  defaultValue: 'mapbox/standard',
-);
+String get _mapboxStyle {
+  final style = runtime_config.mapboxStyle();
+  return style.isEmpty ? 'mapbox/standard' : style;
+}
 
 class MapflowShell extends StatelessWidget {
   const MapflowShell({super.key});

lib/main.dart

@@ -4,13 +4,13 @@ import 'package:mapbox_maps_flutter/mapbox_maps_flutter.dart' as mbx;
 
 import 'app/app.dart';
 import 'shared/auth/telegram_session.dart' as telegram_session;
-
-const _mapboxAccessToken = String.fromEnvironment('MAPBOX_ACCESS_TOKEN');
+import 'shared/runtime_config/runtime_config.dart' as runtime_config;
 
 void main() {
   WidgetsFlutterBinding.ensureInitialized();
-  if (_mapboxAccessToken.isNotEmpty) {
-    mbx.MapboxOptions.setAccessToken(_mapboxAccessToken);
+  final mapboxAccessToken = runtime_config.mapboxAccessToken();
+  if (mapboxAccessToken.isNotEmpty) {
+    mbx.MapboxOptions.setAccessToken(mapboxAccessToken);
   }
   usePathUrlStrategy();
   telegram_session.configureTelegramWebApp();

lib/shared/runtime_config/runtime_config.dart

@@ -0,0 +1,2 @@
+export 'runtime_config_stub.dart'
+    if (dart.library.js_interop) 'runtime_config_web.dart';

lib/shared/runtime_config/runtime_config_stub.dart

@@ -0,0 +1,3 @@
+String mapboxAccessToken() => '';
+
+String mapboxStyle() => '';

lib/shared/runtime_config/runtime_config_web.dart

@@ -0,0 +1,13 @@
+import 'dart:js_interop';
+
+@JS('__MAPFLOW_CONFIG__')
+external _MapflowConfig? get _config;
+
+extension type _MapflowConfig(JSObject _) implements JSObject {
+  external JSString? get mapboxAccessToken;
+  external JSString? get mapboxStyle;
+}
+
+String mapboxAccessToken() => _config?.mapboxAccessToken?.toDart ?? '';
+
+String mapboxStyle() => _config?.mapboxStyle?.toDart ?? '';