A whole lot of stuff

lib/main.dart

@@ -5,11 +5,18 @@ import 'screens/main_shell.dart';
 import 'screens/user_agreement_screen.dart';
 import 'services/app_state.dart';
 import 'theme/app_theme.dart';
+import 'widgets/ad_free_upsell_dialog.dart';
 
 void main() {
   runApp(const FuelTaxTrackerApp());
 }
 
+/// A stable handle on the navigator so [AppState.onAdWatched] can show the
+/// "remove ads" dialog from wherever the app happens to be — it fires from
+/// deep inside a background sync, not from a widget's own build method, so
+/// there's no local [BuildContext] to reach for at that point.
+final navigatorKey = GlobalKey<NavigatorState>();
+
 class FuelTaxTrackerApp extends StatelessWidget {
   const FuelTaxTrackerApp({super.key});
 
@@ -18,13 +25,20 @@ class FuelTaxTrackerApp extends StatelessWidget {
     return ChangeNotifierProvider(
       create: (_) => AppState()..init(),
       child: Consumer<AppState>(
-        builder: (context, appState, _) => MaterialApp(
-          title: 'Fuel Tax Tracker',
-          theme: AppTheme.light,
-          darkTheme: AppTheme.dark,
-          themeMode: appState.themeMode,
-          home: const AppRoot(),
-        ),
+        builder: (context, appState, _) {
+          appState.onAdWatched ??= () {
+            final dialogContext = navigatorKey.currentContext;
+            if (dialogContext != null) showAdFreeUpsellDialog(dialogContext);
+          };
+          return MaterialApp(
+            navigatorKey: navigatorKey,
+            title: 'Fuel Tax Tracker',
+            theme: AppTheme.light,
+            darkTheme: AppTheme.dark,
+            themeMode: appState.themeMode,
+            home: const AppRoot(),
+          );
+        },
       ),
     );
   }