fix userfront verify link routing

userfront/test/verification_route_policy_test.dart

@@ -0,0 +1,55 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:userfront/core/i18n/locale_registry.dart';
+import 'package:userfront/features/auth/domain/verification_completion_route.dart';
+
+void main() {
+  setUpAll(LocaleRegistry.primeWithDefaults);
+
+  group('verification route policy', () {
+    test('루트 인증 payload는 전용 verify 라우트로 정리한다', () {
+      final redirect = buildDedicatedVerificationRedirect(
+        Uri.parse(
+          '/?loginId=e2e%40example.com&code=654321&pendingRef=pending-root&utm=drop',
+        ),
+        localeCode: 'ko',
+      );
+
+      expect(
+        redirect,
+        '/ko/verify?loginId=e2e%40example.com&code=654321&pendingRef=pending-root',
+      );
+    });
+
+    test('signin 인증 payload도 로그인 화면에서 직접 소비하지 않는다', () {
+      final redirect = buildDedicatedVerificationRedirect(
+        Uri.parse('/ko/signin?t=magic-token&utm=drop'),
+        localeCode: 'ko',
+      );
+
+      expect(redirect, '/ko/verify?t=magic-token');
+    });
+
+    test('인증 payload 여부를 식별한다', () {
+      expect(hasVerificationPayload(Uri.parse('/?t=magic-token')), isTrue);
+      expect(
+        hasVerificationPayload(
+          Uri.parse('/ko/signin?loginId=e2e%40example.com&code=654321'),
+        ),
+        isTrue,
+      );
+      expect(
+        hasVerificationPayload(Uri.parse('/ko/signin?code=654321')),
+        isFalse,
+      );
+    });
+
+    test('이미 전용 verify 라우트면 다시 리다이렉트하지 않는다', () {
+      final redirect = buildDedicatedVerificationRedirect(
+        Uri.parse('/ko/verify?loginId=e2e%40example.com&code=654321'),
+        localeCode: 'ko',
+      );
+
+      expect(redirect, isNull);
+    });
+  });
+}