Fix white screen after login: pushReplacement to DashboardScreen; main decides home by email presence; add missing imports

lib/auth_screen.dart

@@ -1,6 +1,9 @@
 import 'package:flutter/material.dart';
 import 'package:google_sign_in/google_sign_in.dart';
+import 'package:provider/provider.dart';
 import 'package:login_vault_app/auth_service.dart';
+import 'package:login_vault_app/dashboard_screen.dart';
+import 'package:login_vault_app/theme_provider.dart';
 
 /// First-launch screen: register with email+password, or with Google.
 class AuthScreen extends StatefulWidget {
@@ -18,6 +21,19 @@ class _AuthScreenState extends State<AuthScreen> {
   bool _busy = false;
   String? _error;
 
+  void _goToDashboard(String email) {
+    if (!mounted) return;
+    Navigator.of(context).pushReplacement(
+      MaterialPageRoute(
+        builder: (_) => DashboardScreen(
+          auth: widget.auth,
+          theme: Provider.of<ThemeProvider>(context, listen: false),
+          email: email,
+        ),
+      ),
+    );
+  }
+
   Future<void> _submitEmail() async {
     setState(() => _busy = true);
     final email = _emailCtrl.text.trim();
@@ -36,12 +52,11 @@ class _AuthScreenState extends State<AuthScreen> {
         } else if (!ok) {
           setState(() => _error = 'Password aplikasi salah');
         } else {
-          // success -> pop true
-          if (mounted) Navigator.pop(context, true);
+          _goToDashboard(email);
         }
       } else {
         await widget.auth.registerWithEmail(email, pass);
-        if (mounted) Navigator.pop(context, true);
+        _goToDashboard(email);
       }
     } catch (e) {
       setState(() => _error = e.toString());
@@ -57,7 +72,7 @@ class _AuthScreenState extends State<AuthScreen> {
       final account = await gs.signIn();
       if (account?.email != null) {
         await widget.auth.registerWithGoogle(account!.email);
-        if (mounted) Navigator.pop(context, true);
+        _goToDashboard(account.email);
       } else {
         setState(() => _error = 'Google sign-in dibatalkan');
       }