Show accepted signup delivery without a second send step (#62)

frontend/packages/sxchnge_auth/lib/src/mappers/backend.dart

@@ -12,9 +12,13 @@ abstract final class BackendMapper {
     return VerificationResult(isSimulated: false, verifiedEmail: dto.email);
   }
 
-  static AuthResult signup(BackendDTO dto) {
+  static AuthResult signup(BackendDTO dto, {required String email}) {
     if (dto.userId.isEmpty) throw const FormatException('Missing user');
-    return AuthResult(userId: dto.userId, isSimulated: false);
+    return AuthResult(
+      userId: dto.userId,
+      isSimulated: false,
+      delivery: VerificationDelivery(email: email, isSimulated: false),
+    );
   }
 
   static FactorChallenge challenge(BackendDTO dto, String id) {