refactor(router): Align type hint for optional parameter in docblock

src/Libs/Router.php

@@ -20,6 +20,7 @@ class Router
     private static array $put    = [];
     private static array $patch  = [];
     private static array $delete = [];
+
     /**
      * Stores the method and index of the last configured route, e.g., ['get', 0].
      * Used for chaining methods like middleware() or reconfigure().
@@ -27,12 +28,14 @@ class Router
      * @var array $last
      */
     private static array $last;
+
     /**
      * Stores the parameters extracted from the current matching route.
      *
      * @var Neuron $params
      */
     public static Neuron $params;
+
     /**
      * The callback function to be executed when no route matches.
      *
@@ -132,7 +135,7 @@ class Router
      * Only one middleware can be added at a time.
      *
      * @param callable $callback
-     * @param int      $priority Optional priority for the middleware execution order.
+     * @param int|null $priority Optional priority for the middleware execution order.
      *
      * @return static
      *                Returns the current instance.