Refactor workflow guard logic and add internal methods

Removed guard logic from EntityWorkflowTransitionEventSubscriber and created a new EntityWorkflowGuardTransition class for separation of concerns. Marked several setter methods in EntityWorkflowStepSignature as internal to guide proper usage. Added comprehensive tests to ensure the new guard logic functions correctly.

src/Bundle/ChillMainBundle/Entity/Workflow/EntityWorkflowStepSignature.php

@@ -105,6 +105,11 @@ class EntityWorkflowStepSignature implements TrackCreationInterface, TrackUpdate
         return $this->state;
     }
 
+    /**
+     * @return $this
+     *
+     * @internal You should not use this method directly, use @see{Chill\MainBundle\Workflow\SignatureStepStateChanger} instead
+     */
     public function setState(EntityWorkflowSignatureStateEnum $state): EntityWorkflowStepSignature
     {
         $this->state = $state;
@@ -117,6 +122,11 @@ class EntityWorkflowStepSignature implements TrackCreationInterface, TrackUpdate
         return $this->stateDate;
     }
 
+    /**
+     * @return $this
+     *
+     * @internal You should not use this method directly, use @see{Chill\MainBundle\Workflow\SignatureStepStateChanger} instead
+     */
     public function setStateDate(?\DateTimeImmutable $stateDate): EntityWorkflowStepSignature
     {
         $this->stateDate = $stateDate;
@@ -129,6 +139,11 @@ class EntityWorkflowStepSignature implements TrackCreationInterface, TrackUpdate
         return $this->zoneSignatureIndex;
     }
 
+    /**
+     * @return $this
+     *
+     * @internal You should not use this method directly, use @see{Chill\MainBundle\Workflow\SignatureStepStateChanger} instead
+     */
     public function setZoneSignatureIndex(?int $zoneSignatureIndex): EntityWorkflowStepSignature
     {
         $this->zoneSignatureIndex = $zoneSignatureIndex;