fix: patch up namespace issue

src/Router.php

@@ -143,6 +143,7 @@ public static function match(string $methods, string $pattern, $handler)
             static::$namedRoutes[$routeOptions['name']] = $pattern;
         }
 
+
         if ($routeOptions['middleware']) {
             static::before($methods, $rawPattern, $routeOptions['middleware']);
         }

src/Router/Core.php

@@ -171,6 +171,19 @@ protected static function mapHandler($handler, $options): array
                         || is_numeric($key) && is_string($value) && strpos($value, '@')
                     ) {
                         $handler = $handler[$key];
+
+                        if (is_string($handler)) {
+                            $namespace = static::$namespace;
+
+                            if ($options['namespace']) {
+                                static::$namespace = $options['namespace'];
+                            }
+
+                            $handler = str_replace('\\\\', '\\', static::$namespace . "\\$handler");
+
+                            static::$namespace = $namespace;
+                        }
+
                         unset($handlerData[$key]);
                         break;
                     }