Add const qualifier to CssReloadHelper::changeCssFile

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: BBaoVanC

include/util/css_reload_helper.hpp

@@ -20,7 +20,7 @@ class CssReloadHelper {
 
   virtual void monitorChanges();
 
-  virtual void changeCssFile(std::string newCssFile);
+  virtual void changeCssFile(const std::string& newCssFile);
 
  protected:
   std::vector<std::string> parseImports(const std::string& cssFile);