Fix OpenEnv validation: add uv.lock, scripts entry, openenv-core dep, main()

Fix /reset endpoint to accept empty POST body for OpenEnv checker

Fix: redirect root / to Gradio UI at /ui by SpandanM110

Add Gradio UI, switch to Qwen2.5-72B-Instruct on HF Inference API by SpandanM110

Initial submission: OCR Table RL Environment for OpenEnv RL Challenge by SpandanM110