Handle from_docker_image failure gracefully, fall back to HF Space URL

Match exact [START]/[STEP]/[END] format from sample inference.py

Fix Docker build + rewrite inference.py to follow OpenEnv sample pattern

Add missing uv.lock for openenv validate

Fix Phase 2: add [START]/[STEP]/[END] structured output to inference.py

HF

Initial DataClean OpenEnv Space