테넌트 접근 제한 안내화면 개선

userfront/lib/features/auth/presentation/consent_screen.dart

@@ -1,3 +1,5 @@
+import 'dart:convert';
+
 import 'package:flutter/material.dart';
 import 'package:go_router/go_router.dart';
 import 'package:userfront/i18n.dart';
@@ -5,11 +7,18 @@ import 'package:userfront/core/i18n/locale_utils.dart';
 import 'package:userfront/core/services/auth_proxy_service.dart';
 import 'package:userfront/core/services/web_window.dart';
 import 'package:userfront/core/ui/toast_service.dart';
+import 'package:userfront/features/auth/domain/consent_error_routing.dart';
 
 class ConsentScreen extends StatefulWidget {
   final String consentChallenge;
+  final Future<Map<String, dynamic>> Function(String consentChallenge)?
+  consentInfoLoader;
 
-  const ConsentScreen({super.key, required this.consentChallenge});
+  const ConsentScreen({
+    super.key,
+    required this.consentChallenge,
+    this.consentInfoLoader,
+  });
 
   @override
   State<ConsentScreen> createState() => _ConsentScreenState();
@@ -93,9 +102,9 @@ class _ConsentScreenState extends State<ConsentScreen> {
 
   Future<void> _fetchConsentInfo() async {
     try {
-      final info = await AuthProxyService.getConsentInfo(
-        widget.consentChallenge,
-      );
+      final loader =
+          widget.consentInfoLoader ?? AuthProxyService.getConsentInfo;
+      final info = await loader(widget.consentChallenge);
 
       // [Skip Logic] 백엔드에서 자동 승인되어 리다이렉트 URL이 온 경우 즉시 이동
       if (info['redirectTo'] != null) {
@@ -139,6 +148,35 @@ class _ConsentScreenState extends State<ConsentScreen> {
         _consentInfo = info;
         _isLoading = false;
       });
+    } on AuthProxyException catch (e) {
+      if (shouldRouteConsentErrorToErrorScreen(e)) {
+        if (!mounted) {
+          return;
+        }
+        final localeCode =
+            extractLocaleFromPath(Uri.base) ?? resolvePreferredLocaleCode();
+        final target = buildLocalizedPath(
+          localeCode,
+          Uri(
+            path: '/error',
+            queryParameters: {
+              'error': e.errorCode,
+              'error_description': e.message,
+              if (e.details != null) 'details': jsonEncode(e.details),
+            },
+          ),
+        );
+        context.go(target);
+        return;
+      }
+      setState(() {
+        _error = tr(
+          'msg.userfront.consent.load_error',
+          fallback: 'Failed to load consent information: {{error}}',
+          params: {'error': e.message},
+        );
+        _isLoading = false;
+      });
     } catch (e) {
       setState(() {
         _error = tr(