Add handball court support

[sousousore1]

Summary

• Add an IHF-standard handball court configuration with court dimensions, key vertices, labels, colors, and compatibility exports.
• Add handball court rendering utilities for drawing the court, points, and paths.
• Include the 4 m diameter throw-off area and rulebook-aligned free-throw and substitution markings.
• Add focused tests for the handball configuration geometry and metadata.
• Add examples/handball with a runnable example script, static court rendering notebook, setup files, and ignored output directories.
• Add Roboflow Universe dataset references and training notebooks for handball player, ball, and court keypoint models.

Roboflow datasets

• Player detection: https://universe.roboflow.com/project-k1mun/handball_player_detection
• Ball detection: https://universe.roboflow.com/handballdetection/handball-ballon
• Ball detection: https://universe.roboflow.com/handball-detection/ball-only-detection
• Court keypoint detection: https://universe.roboflow.com/handball-wckh8/handball-keypoint-detection-ndvsl

Notes

• Training notebooks use numpy<2 to avoid PyTorch/NumPy ABI issues in notebook runtimes.
• Training notebooks use yolov8 exports because the handball keypoint dataset does not support yolov11 export.

Validation

• python3 -m unittest discover tests
• python3 -m compileall examples/handball sports tests
• Notebook JSON parse for all examples/handball/notebooks/*.ipynb files