fix: use CPU mode for model pre-download during Docker build

Dockerfile

@@ -83,8 +83,9 @@ RUN echo "========== STEP 4: Installing Python dependencies ==========" && \
     echo "========== Python dependencies installed =========="
 
 # Pre-download PaddleOCR-VL-1.5 model at build time (avoids download on first request)
+# CUDA_VISIBLE_DEVICES="" forces CPU mode since no GPU is available during build
 RUN echo "========== STEP 5: Pre-downloading PaddleOCR-VL-1.5 model ==========" && \
-    python -c "from paddleocr import PaddleOCRVL; PaddleOCRVL()" && \
+    CUDA_VISIBLE_DEVICES="" python -c "from paddleocr import PaddleOCRVL; PaddleOCRVL(use_gpu=False)" && \
     echo "Model cache summary:" && \
     du -sh /home/user/.cache/paddleocr 2>/dev/null || echo "  PaddleOCR cache: (empty)" && \
     du -sh /home/user/.cache/huggingface 2>/dev/null || echo "  HF cache: (empty)" && \