[maxkra15]

Description

Adds IsaacContrib-Conveyor-Racetrack-Transfer-v0: a Franka continuously transfers four cubes between counter-rotating racetrack conveyors. Preserves 123 policy observations, eight actions, ordered joints, 120 Hz physics and the 60 Hz policy rate.

Reset recipes reuse the NIST Sampler, Beta strategy and shared SuccessMonitor. The task uses standard MeshFileCfg.TriangleMeshCfg and cuboid spawning; no custom core mesh API is needed. Tool references bind once before managers, arm targets use one buffer, and final config validation has one owner.

Depends only on #8327. Review the task changes. Warehouse sorting is #8332; optional CPU PhysX is #8794. #6952 records combined validation. #8326 has been superseded by the existing mesh spawner.

Validation

• Nine racetrack task/geometry cases passed; the complete stack passes 38 focused cases.
• 90 mesh inputs and 16 native model arrays preserve geometry, contacts and materials. Six cuboid callers preserve their finalized colors.
• 84 action/tool/reset tensors match before and after cleanup.
• Current-main combined playback: eight GPU environments, 1,200 steps, 15 transfers, zero failures/non-finite observations.
• Full formatting/lint/changelog/LFS, generated environment browser and lock checks passed.

Checklist

• Followed contribution and test-audit guidance.
• Ran focused tests and repository formatting/lint checks.
• Updated documentation and package changelog.
• Contributor already listed in CONTRIBUTORS.md.