fix(promo-codes): fix serializer tests and resolve D3 deviation

Serializer unit tests (testSerializerAutoApplyField,
testSerializerRemainingQuantityPerAccount, testSerializerAutoApplyEmailLinkedType)
were failing because bare model instances lacked a Summit association, causing
getSummitId() to call getId() on null. Added buildMockSummitForSerializer()
helper and setSummit() calls in all three tests. Updated D3 deviation status
to RESOLVED — AllowedEmailDomainsArray custom rule was already implemented.

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

Author: caseylocker

app/ModelSerializers/Summit/Registration/PromoCodes/SpeakerSummitRegistrationDiscountCodeSerializer.php

@@ -61,6 +61,7 @@ public function serialize($expand = null, array $fields = [], array $relations =
                             );
                         }
                     }
+                        break;
                     case 'owner_name': {
                         if($code->hasSpeaker()){
                             $values['owner_name'] = $code->getSpeaker()->getFullName();

app/ModelSerializers/Summit/Registration/PromoCodes/SpeakerSummitRegistrationPromoCodeSerializer.php

@@ -61,6 +61,7 @@ public function serialize($expand = null, array $fields = [], array $relations =
                             );
                         }
                     }
+                        break;
                     case 'owner_name': {
                         if($code->hasSpeaker()){
                             $values['owner_name'] = $code->getSpeaker()->getFullName();

app/Repositories/Summit/DoctrineSummitRegistrationPromoCodeRepository.php

@@ -701,8 +701,8 @@ public function getDiscoverableByEmailForSummit(Summit $summit, string $email):
 
             // Email-linked types: match by associated member/speaker email
             if ($code instanceof MemberSummitRegistrationPromoCode || $code instanceof MemberSummitRegistrationDiscountCode) {
-                $owner = $code->getOwner();
-                if (!is_null($owner) && strtolower($owner->getEmail()) === $email && $code->isLive()) {
+                $ownerEmail = $code->getOwnerEmail();
+                if (!empty($ownerEmail) && strtolower($ownerEmail) === $email && $code->isLive()) {
                     $results[] = $code;
                 }
                 continue;