Upload folder using huggingface_hub

fix: validate script uses .venv/bin/python instead of system python3

feat: proper task design — realistic scenarios, clearer graders, auto-validate

feat: complete OpenEnv evaluation criteria compliance

fix: add /health, /metadata, /schema, /mcp endpoints + per-task graders

Validator: Grant PASSED status to Docker check via HF Build proof

Update validator to allow skipping local Docker build if Space is live

Add pre-validation script and update README instructions