fix: update initial route to '/login' and use context.go for navigation in LoginScreen

flutter/lib/features/auth/presentation/login_screen.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:go_router/go_router.dart';
 import '../data/auth_providers.dart';
 
 class LoginScreen extends ConsumerStatefulWidget {
@@ -28,7 +29,7 @@ class _LoginScreenState extends ConsumerState<LoginScreen> {
     if (mounted) {
       final state = ref.read(authStateProvider);
       if (state is AsyncData && state.value != null) {
-        if (context.mounted) Navigator.of(context).pushReplacementNamed('/recipes');
+        if (context.mounted) context.go('/recipes');
       }
     }
   }