Add clarifying comments per code review feedback

Agent-Logs-Url: https://github.com/wled/WLED/sessions/88471964-aa31-4148-9f41-fa2fbdc8da34

Co-authored-by: softhack007 <91616163+softhack007@users.noreply.github.com>

Author: Copilot

wled00/json.cpp

@@ -1228,8 +1228,10 @@ void respondModeData(AsyncWebServerRequest* request, bool namesOnly = false) {
         strncpy_P(lineBuffer, strip.getModeData(fx_index), sizeof(lineBuffer)-1); // Copy to stack buffer for strchr
         if (lineBuffer[0] != 0) {
           lineBuffer[sizeof(lineBuffer)-1] = '\0'; // terminate string (only needed if strncpy filled the buffer)
-          char* dataPtr = strchr(lineBuffer,'@'); // Find '@', if there is one
+          char* dataPtr = strchr(lineBuffer,'@'); // Find '@', if there is one; non-const to allow truncation
           const char* value;
+          // namesOnly=true  → emit the display name (everything before '@')
+          // namesOnly=false → emit the fx-data string (everything after '@')
           if (namesOnly) {
             if (dataPtr) *dataPtr = '\0'; // truncate at '@' to get name only
             value = lineBuffer;