Updates to add more ads and fix ad types.

lib/screens/confirm_fuel_entry_screen.dart

@@ -54,6 +54,8 @@ class _ConfirmFuelEntryScreenState extends State<ConfirmFuelEntryScreen> {
     _totalController = TextEditingController(
       text: widget.parsed.totalCost?.toStringAsFixed(2) ?? '',
     );
+    // So an ad is ready by the time _save() finishes without delaying it.
+    context.read<AppState>().preloadFuelSaveAd();
   }
 
   @override