Use --index-url PaddlePaddle index for GPU 3.0.0 + PyPI as fallback

Fix: direct wheel URL for paddlepaddle-gpu 3.0.0, numpy<2.0, add opencv-headless

Fix: use PaddlePaddle index for GPU 3.0.0 (not on PyPI)

Optimize: use predict() for native GPU batching, improve result parsing

Add PaddleOCR custom inference handler

initial commit