misc!: remove node visitor feature

This feature was a relic of the first release of the library. It had
strong design issues and was going to become a huge blocker for upcoming
features.

Although it was never documented, it may have been used in applications;
there will be no replacement for this feature. If this becomes an issue
for existing applications, an issue can be created in the repository to
discuss other possible solutions.

src/Library/Container.php

@@ -46,7 +46,6 @@
 use CuyZ\Valinor\Mapper\Tree\Builder\StrictNodeBuilder;
 use CuyZ\Valinor\Mapper\Tree\Builder\UnionNodeBuilder;
 use CuyZ\Valinor\Mapper\Tree\Builder\ValueAlteringNodeBuilder;
-use CuyZ\Valinor\Mapper\Tree\Builder\VisitorNodeBuilder;
 use CuyZ\Valinor\Mapper\Tree\Visitor\AttributeShellVisitor;
 use CuyZ\Valinor\Mapper\Tree\Visitor\ShellVisitor;
 use CuyZ\Valinor\Mapper\TreeMapper;
@@ -125,7 +124,6 @@ public function __construct(Settings $settings)
 
                 $builder = new CasterProxyNodeBuilder($builder);
                 $builder = new IterableNodeBuilder($builder);
-                $builder = new VisitorNodeBuilder($builder, $settings->nodeVisitors);
                 $builder = new ValueAlteringNodeBuilder(
                     $builder,
                     new FunctionsContainer(

src/Library/Settings.php

@@ -5,7 +5,6 @@
 namespace CuyZ\Valinor\Library;
 
 use CuyZ\Valinor\Mapper\Tree\Message\ErrorMessage;
-use CuyZ\Valinor\Mapper\Tree\Node;
 use DateTimeImmutable;
 use DateTimeInterface;
 use Psr\SimpleCache\CacheInterface;
@@ -26,9 +25,6 @@ final class Settings
     /** @var list<callable> */
     public array $valueModifier = [];
 
-    /** @var array<callable(Node): void> */
-    public array $nodeVisitors = [];
-
     /** @var CacheInterface<mixed> */
     public CacheInterface $cache;
 

src/MapperBuilder.php

@@ -8,7 +8,6 @@
 use CuyZ\Valinor\Library\Container;
 use CuyZ\Valinor\Library\Settings;
 use CuyZ\Valinor\Mapper\Tree\Message\ErrorMessage;
-use CuyZ\Valinor\Mapper\Tree\Node;
 use CuyZ\Valinor\Mapper\TreeMapper;
 use Psr\SimpleCache\CacheInterface;
 use Throwable;
@@ -225,16 +224,6 @@ public function alter(callable $callback): self
         return $clone;
     }
 
-    /**
-     * @param callable(Node): void $callback
-     */
-    public function visit(callable $callback): self
-    {
-        $this->settings->nodeVisitors[] = $callback;
-
-        return $this;
-    }
-
     /**
      * Enables flexible mode for the mapper:
      *