- Add warn! macro import to javascript.rs module
- Add warning log at detect_javascript() entry point stating execution is not supported
- Update verification note for bf-2pxsu
This complements the logging already present in detection.rs (from bf-2pyg1) by ensuring the JavaScript module itself has appropriate logging.
Per TH-04 threat model, pdftract NEVER executes embedded JavaScript; this logging explicitly confirms detection-only behavior.