fix: patch torch._pytree.register_constant + tighten torchao/transformers pins

Force-downgrade torchao to 0.6.1 after unsloth to fix register_constant crash

Upgrade to PyTorch 2.6.0 base image for native torchao support

Fix torchao int1 error by pinning to 0.6.1

Fix torch.int1 error by downgrading torchao

Fix HF Docker build: install git for unsloth

Initial commit for CodeForge GRPO training