Implement Phase 1 of custom Kirby plugin for editing interactive maps:
- OpenStreetMap base layer with MapLibre GL JS
- Click to add markers, drag to reposition
- Marker list sidebar with selection and deletion
- Auto-save with debounce (YAML format)
- Add marker button creates marker at current map center
- Max 50 markers per map (configurable)
- Clean UI with marker counter
Blueprint updated to use new map-editor field type instead of placeholder.
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
