Make marimo notebooks MoLab-compatible with pinned polyplot install

[ckmah]

Summary

• enforce Hugging Face-only dataset loading in both marimo notebooks (no raw GitHub or local fallbacks)
• move and rename development notebook from notebook.py to dev/full_demo.py
• simplify notebook data configuration to one variable: POLYPLOT_PARQUET_URL
• remove private-token auth and repo/ref/file environment variable breakdown
• add robust remote parquet loading in notebooks for http(s) URLs by downloading bytes to a temporary local parquet file before calling geopandas.read_parquet
• reorganize packaging dependencies (pyproject.toml):
  • trim core runtime dependencies
  • add test and docs optional extras
  • keep dev group for local contributor workflows
• add CI and manual publish workflows:
  • .github/workflows/ci.yml
  • .github/workflows/publish-test.yml
  • .github/workflows/publish.yml
  • official PyPI publish remains manual only

Validation

• python3 -m py_compile quickstart.py dev/full_demo.py
• ran quickstart.py in marimo edit mode with marimo-pair installed
• executed notebook cells successfully; no notebook runtime exceptions after HTTP parquet-loader change
• marimo snapshot confirms polyplot viewer UI rendered, including camera/grid/wireframe/opacity controls and tile source endpoint (on-demand tiles from http://127.0.0.1:8765)