Add dataset privacy metadata and CI for launch readiness

[Jakedoes1111]

Summary

• extend the dataset schema with explicit privacy/provenance fields, update provider flows to populate them, and surface the metadata in the UI
• refresh documentation, sample data, and environment scaffolding to reflect the new launch expectations and gate demo providers behind an env flag
• add smoke tests for filters/importer/timeline/compass alongside a GitHub Actions CI workflow running lint, tests, and build

Testing

• npm test -- --run
• npm run build

---

Codex Task