Use const in for loop

esphome/nspanel_esphome_core.yaml

@@ -1735,7 +1735,7 @@ text_sensor:
 
           std::string result;
           bool last_was_underscore = false;
-          for (char& c : raw_name) {
+          for (const char& c : raw_name) {
             if (isalnum(c)) {
               result += tolower(c);  // Add alphanumeric characters as lowercase
               last_was_underscore = false;