feat: initialize offline multiview pose tracking experiment

Set up pose_tracking_exp as a uv-managed Python package for offline multiview body tracking experiments.

This initial commit includes:

- the typed package scaffold, CLI entrypoints, and repo-local uv configuration

- scene and replay loaders for generic JSON replays and ActualTest parquet inputs

- ParaJumping payload conversion and RTMPose-to-body20 normalization

- a custom articulated tracker with tentative, active, and lost lifecycle handling

- RPT-backed proposal generation, camera convention handling, and multiview reprojection updates

- regression tests for normalization, camera conventions, ActualTest ingestion, seeding, and tracker smoke flows

- project documentation covering extrinsic formats and the ActualTest calibration caveat

.gitignore

@@ -0,0 +1,5 @@
+.pytest_cache/
+.venv/
+.venv-pypi/
+__pycache__/
+*.pyc