Add portable XHand RL training snapshot (3395 grasps)

Single ZIP snapshot containing 3395 finalized grasp PKLs, 150 referenced object meshes, XHand robot assets, portable indexes, configs, and checksums. Videos, logs, checkpoints, temporary files, failed rollouts, and SQLite state are excluded.

xhand_rl_full_training_v1_snapshot_20260803_172453.zip

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:c7a432c725d078d5f6427ea9158b6a8e0f93e19d7c4ac74d10831533c53b84b9
+size 832660240