테넌트 접근 제한 안내화면 개선

userfront/lib/core/services/auth_proxy_service.dart

@@ -396,8 +396,14 @@ class AuthProxyService {
         return jsonDecode(response.body);
       } else {
         final errorBody = jsonDecode(response.body);
-        throw Exception(
-          errorBody['error'] ?? tr('err.userfront.auth_proxy.consent_fetch'),
+        final rawDetails = errorBody['details'];
+        throw AuthProxyException(
+          errorCode: (errorBody['code'] ?? '').toString(),
+          message:
+              (errorBody['error'] ??
+                      tr('err.userfront.auth_proxy.consent_fetch'))
+                  .toString(),
+          details: rawDetails is Map<String, dynamic> ? rawDetails : null,
         );
       }
     } finally {
@@ -1105,3 +1111,18 @@ class AuthProxyService {
     }
   }
 }
+
+class AuthProxyException implements Exception {
+  final String errorCode;
+  final String message;
+  final Map<String, dynamic>? details;
+
+  const AuthProxyException({
+    required this.errorCode,
+    required this.message,
+    this.details,
+  });
+
+  @override
+  String toString() => message;
+}