posttrain-ckpt-2000 — bounded post-train of the released T-Rex midtrain checkpoint

Weights of the 2000-step post-training run trex_posttrain_public_0728_1300 from https://github.com/physercoe/trex-repro (see docs/EVAL.md).

Base: officially released T-Rex midtrain checkpoint (upstream: https://github.com/ZhuoyangLiu2005/T-Rex; arXiv:2606.17055).
Data: 144 episodes (shard 0) of the public zekaiwang/trex_dataset, adapted on-the-fly to the eef-62 schema (scripts/trex_public_dataset.py).
Config: MAX_STEPS=2000, bsz 4, lr 1e-4, bf16; train loss 1.48 → ~0.07–0.23; val @1999 act=0.0588, tac=0.1152.
Files: model.pt (single-file torch checkpoint, ~8.5 GB — weights only, no optimizer state), config.json, training_args.json, stats_data.json, processor/ (tokenizer/preprocessor). Load with the repo's own model_load (repo/scripts/test.py) — the format round-trips through its auto-detect.
Finding (candid): open-loop, this post-train did not make the tactile expert input-responsive (probes ~5e-4 before and after) — see the repo README and docs/EVAL.md, Finding P3.

License: MIT. Derived from the T-Rex authors' released checkpoint — cite arXiv:2606.17055.