fixed birthDate null crash in edit form and documented uploadFile implicit coupling

Author: Lung

src/Event/AbstractContentArbiter.php

@@ -110,7 +110,7 @@ public function __construct()
             placeholder: 'detail.birthPlacePlaceholder',
         );
         $this->uploadFile = new ContentArbiterItem(
-            id: 'uploadFile',
+            id: 'uploadFile', // not a real entity property; templates pass null explicitly, validation skips via required:false
             allowed: false,
             type: ContentArbiterItemType::File,
             order: 90,

src/Event/ContentArbiter/ContentArbiterItem.php

@@ -7,7 +7,7 @@
 class ContentArbiterItem
 {
     /**
-     * @param array<string, string> $options key=dbValue, value=translationKey
+     * @param array<string, string> $options key=dbValue, value=translationKey, backward compatibility for selfMappedOptions
      * @param list<string> $extraClasses
      */
     public function __construct(

src/Participant/Participant.php

@@ -7,11 +7,11 @@
 use DateTimeInterface;
 use kissj\Orm\EntityDatetime;
 use kissj\Participant\Patrol\PatrolParticipant;
-use LeanMapper\Exception\MemberAccessException;
 use kissj\Deal\Deal;
 use kissj\Payment\Payment;
 use kissj\Payment\PaymentStatus;
 use kissj\User\User;
+use LeanMapper\Exception\MemberAccessException;
 use Ramsey\Uuid\Uuid;
 
 /**

src/Templates/translatable/widgets/formFields.twig

@@ -43,7 +43,7 @@
                 class="form-control{% if item.id != 'arrivalDate' and item.id != 'departureDate' %} form-wide{% endif %}"
                 type="date"
                 name="{{ item.id }}"
-                value="{% if item.id == 'birthDate' %}{{ value.format('Y-m-d') ?? 'now - 18 years'|date('Y-m-d') }}{% elseif item.id == 'arrivalDate' %}{{ (value ?? event.startDay)|date('Y-m-d') }}{% elseif item.id == 'departureDate' %}{{ (value ?? event.endDay)|date('Y-m-d') }}{% else %}{{ value }}{% endif %}"
+                value="{% if item.id == 'birthDate' %}{% if value %}{{ value.format('Y-m-d') }}{% else %}{{ 'now - 18 years'|date('Y-m-d') }}{% endif %}{% elseif item.id == 'arrivalDate' %}{{ (value ?? event.startDay)|date('Y-m-d') }}{% elseif item.id == 'departureDate' %}{{ (value ?? event.endDay)|date('Y-m-d') }}{% else %}{{ value }}{% endif %}"
                 {% if item.required %}required="required"{% endif %}
                 {% if item.id == 'birthDate' %}onchange="OnBirthDateChange(this)"{% endif %}
             >