Added a warning about the requirement of `tracker_id` for TraceAnnotator in the `core.py`. Also, included an example image in the TraceAnnotator initialization for better understanding in both `core.py` and `annotators.md`.
Added a warning about the requirement of `tracker_id` for TraceAnnotator in the `core.py`. Also, included an example image in the TraceAnnotator initialization for better understanding in both `core.py` and `annotators.md`.