ENHANCEMENT: implemented CSP

lib/Framework/Router.php

@@ -39,6 +39,9 @@ class Router
             $response = $controllerObj->$action(...$method);
 
             if ($response instanceof Response) {
+                $response->headers->add([
+                    "Content-Security-Policy" => "default-src 'none'; font-src 'self'; style-src 'self'; script-src 'self'; img-src 'self'; require-trusted-types-for 'script'"
+                ]);
                 return $response;
             } else {
                 throw new InvalidArgumentException();