[codex] Add Hugging Face leaderboard Space

[jang1563]

Summary

• add a Gradio Space scaffold for the LabCraft-Eval leaderboard
• publish the live Space at https://huggingface.co/spaces/jang1563/LabCraft-Eval-Leaderboard
• add a dry-run/execute helper for Space uploads
• add unit tests for score aggregation, rendering, and upload planning
• link the live Space from README and HF release docs

Validation

• .venv/bin/ruff check .
• .venv/bin/python -m py_compile spaces/leaderboard/app.py scripts/upload_hf_space.py
• .venv/bin/python -m pytest
• .venv/bin/python scripts/upload_hf_space.py --repo-id example/LabCraft-Eval-Leaderboard
• HF Space published successfully: https://huggingface.co/spaces/jang1563/LabCraft-Eval-Leaderboard
• HF Space runtime verified RUNNING via Hub API