Upgrade to Keras 3.x for model compatibility

Dockerfile

@@ -10,8 +10,11 @@ RUN pip install --no-cache-dir datasets "huggingface-hub>=0.30" "hf-transfer>=0.
 
 # CRITICAL: Install numpy FIRST (pyradiomics needs it at build time)
 RUN pip install --no-cache-dir "numpy<2.0"
-RUN pip install --no-cache-dir tensorflow-cpu==2.15.0
+# Install Keras 3.x and TensorFlow
+RUN pip install --no-cache-dir keras==3.7.0
+RUN pip install --no-cache-dir tensorflow-cpu==2.18.0
 
+# Install pyradiomics separately (needs numpy at build time)
 # Use --no-build-isolation to access already-installed numpy
 RUN pip install --no-cache-dir --no-build-isolation pyradiomics==3.0.1 SimpleITK pynrrd