Fix MapLibre map visualization with working data layers

- Add reactive MapLibre layer updates with viewport data
- Convert DuckDB data to GeoJSON for MapLibre compatibility
- Add colored circle layers with source collection styling
- Fix Plot fallback with world map background for testing
- Remove debug console output and clean up code
- Switch to DataUnbound Labs hosting temporarily to avoid Zenodo rate limiting
- Now both interactive MapLibre map and Plot fallback show data correctly

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: rdhyee