Add support for user signatures in workflow transitions

This update introduces the ability to specify user signatures in workflow transitions. It allows a nullable user to be declared that may be requested to apply a signature. The code now handles the use-case of signing a transition by a user in addition to previous functionality of having it signed by a "Person" entity. Corresponding tests are also updated to validate this new feature.

src/Bundle/ChillMainBundle/Workflow/WorkflowTransitionContextDTO.php

@@ -13,6 +13,7 @@ namespace Chill\MainBundle\Workflow;
 
 use Chill\MainBundle\Entity\User;
 use Chill\MainBundle\Entity\Workflow\EntityWorkflow;
+use Chill\PersonBundle\Entity\Person;
 use Symfony\Component\Validator\Constraints as Assert;
 use Symfony\Component\Validator\Context\ExecutionContextInterface;
 use Symfony\Component\Workflow\Transition;
@@ -52,10 +53,17 @@ class WorkflowTransitionContextDTO
     public array $futureDestEmails = [];
 
     /**
-     * a list of future @see{Person} with will sign the next step.
+     * A list of future @see{Person} with will sign the next step.
+     *
+     * @var list<Person>
      */
     public array $futurePersonSignatures = [];
 
+    /**
+     * An eventual user which is requested to apply a signature.
+     */
+    public ?User $futureUserSignature = null;
+
     public ?Transition $transition = null;
 
     public string $comment = '';