fix: guard home buttons against double-tap double-push

lib/ui/screens/home_screen.dart

@@ -66,10 +66,13 @@ class HomeScreen extends ConsumerWidget {
                           horizontal: 56, vertical: 18),
                       textStyle: Theme.of(context).textTheme.titleLarge,
                     ),
-                    onPressed: () => Navigator.of(context).push(
+                    onPressed: () {
+                      if (!(ModalRoute.of(context)?.isCurrent ?? true)) return;
+                      Navigator.of(context).push(
                         MaterialPageRoute(
                             builder: (_) => const SeasonMapScreen()),
-                    ),
+                      );
+                    },
                     child: Text(l10n.adventure),
                   ),
                   const SizedBox(height: 14),
@@ -80,6 +83,7 @@ class HomeScreen extends ConsumerWidget {
                       textStyle: Theme.of(context).textTheme.titleMedium,
                     ),
                     onPressed: () {
+                      if (!(ModalRoute.of(context)?.isCurrent ?? true)) return;
                       ref.read(gameSessionProvider.notifier).startStage(
                             StageConfig.endless(
                               seed: DateTime.now().millisecondsSinceEpoch,