fix: add JsonSerializable inheritance to Ltree value object

This fix issues when serializing Ltree with Symfony Serializer.

Author: landure

src/MartinGeorgiev/Doctrine/DBAL/Types/ValueObject/Ltree.php

@@ -38,6 +38,12 @@ public static function fromString(string $ltree): static
         return new static($branch); // @phpstan-ignore-line argument.type
     }
 
+    #[\Override]
+    public function jsonSerialize(): array
+    {
+        return $this->branch;
+    }
+
     #[\Override]
     public function createLeaf(string $leaf): static
     {

src/MartinGeorgiev/Doctrine/DBAL/Types/ValueObject/LtreeInterface.php

@@ -4,7 +4,7 @@
 
 namespace MartinGeorgiev\Doctrine\DBAL\Types\ValueObject;
 
-interface LtreeInterface extends \Stringable
+interface LtreeInterface extends \Stringable, \JsonSerializable
 {
     /**
      * @param list<non-empty-string> $branch
@@ -18,6 +18,12 @@ public function __construct(array $branch);
      */
     public static function fromString(string $ltree): static;
 
+    /**
+     * @return list<non-empty-string>
+     */
+    #[\Override]
+    public function jsonSerialize(): array;
+
     /**
      * @param non-empty-string $leaf
      *