Pin transformers<5.0 for EsmModel compatibility

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Dockerfile

@@ -9,10 +9,10 @@ ENV DEBIAN_FRONTEND=noninteractive \
 # Set working directory
 WORKDIR /workspace
 
-# Install chai_lab and transformers in a single layer
+# Install chai_lab and compatible transformers in a single layer
 RUN pip install --no-cache-dir \
     chai_lab==0.5.2 \
-    "transformers>=4.30.0"
+    "transformers>=4.30.0,<5.0.0"
 
 # Verify installations
 RUN python -c "import torch; print(f'PyTorch: {torch.__version__}')" && \