Fix PyTorch pip dependency sequence

Dockerfile

@@ -24,14 +24,16 @@ RUN apt-get update && apt-get install -y \
     && rm -rf /var/lib/apt/lists/*
 USER user
 
-# Copy requirements and install via standard pip
-# (Pip handles Linux wheels perfectly, unlike Windows where Conda is needed)
-COPY --chown=user:user requirements.txt .
-RUN pip install --no-cache-dir --user -r requirements.txt
+# 1. Install PyTorch FIRST (Required for PyG C++ extensions)
+RUN pip install --no-cache-dir --user torch==2.2.0+cpu torchvision==0.17.0+cpu -f https://download.pytorch.org/whl/cpu
 
-# Install PyTorch Geometric dependencies (Sparse/Scatter) for Linux CPU natively
+# 2. Install PyTorch Geometric dependencies (Sparse/Scatter) natively from PyG wheel index
 RUN pip install --no-cache-dir --user torch-scatter torch-sparse -f https://data.pyg.org/whl/torch-2.2.0+cpu.html
 
+# 3. Copy requirements and install the rest (It will skip torch and torch-scatter since they are already installed)
+COPY --chown=user:user requirements.txt .
+RUN pip install --no-cache-dir --user -r requirements.txt -f https://data.pyg.org/whl/torch-2.2.0+cpu.html
+
 # Copy the rest of the application
 COPY --chown=user:user . .