chore: update Space title to DataFlow-VQA

fix: upgrade to gradio 5.25 to fix bool-schema TypeError in gradio_client

fix: use Python 3.11 to avoid whylogs-sketching build failure on 3.13

refactor: demo now wraps Stage1 VQA extraction pipeline

fix: upgrade to gradio 5.x to match open-dataflow requirement

initial hf spaces demo