fix: upgrade PyTorch to 2.5.1 to fix unsloth_zoo AttributeError on torch._inductor.config

hf_training/Dockerfile

@@ -5,6 +5,12 @@ RUN apt-get update && apt-get install -y git && rm -rf /var/lib/apt/lists/*
 
 WORKDIR /app
 
+# Upgrade PyTorch to 2.5.1 (cu121) — unsloth_zoo requires torch._inductor.config
+# which only became an accessible attribute in PyTorch 2.4+
+RUN pip install --upgrade --no-cache-dir \
+    torch==2.5.1 torchvision torchaudio \
+    --index-url https://download.pytorch.org/whl/cu121
+
 # Install Unsloth and training dependencies
 RUN pip install --no-cache-dir \
     "unsloth[colab-new] @ git+https://github.com/unslothai/unsloth.git" \