Add Configs and Benchmarks

Config additions should follow the existing split:

• datasets/ for dataset facts
• benchmarks/ for dataset + detector + ReID selection
• detectors/ for detector profiles
• reid/ for ReID profiles
• trackers/ for tracker defaults and tuning spaces

Common change sets

Adding a new benchmark usually means:

1. add a dataset YAML
2. add a benchmark YAML
3. confirm detector and ReID profiles already exist or add them
4. update docs if the benchmark becomes a documented workflow

Adding a tuned tracker usually means:

1. update the tracker YAML
2. validate track, eval, and tune
3. document any new behavior or defaults