Enhance population counting accuracy and add comprehensive geoJSON exports

Population System Fixes:
- Fix province, culture, and religion population calculations to exclude rural population from cells without burgs
- Burgs now represent ALL population for their cells (both urban and rural components)
- Eliminate double-counting where cell populations were incorrectly added to burg populations

Export Enhancements:
- Add complete geoJSON export for burgs with all settlement properties
- Enhance routes geoJSON export to include type and feature metadata
- Add missing length and width properties to rivers geoJSON export
- Fix burg coordinate system to match CSV export format with xWorld/yWorld fields

UI Improvements:
- Add burgs export button to geoJSON export interface
- Fix vite module loading issue by adding type="module" to notes-editor.js script tag

Documentation:
- Create comprehensive QGIS Style Conversion guide with route types, burg features, and relief rendering methods
- Add WKT coordinate reference system definition for Fantasy Map Cartesian CRS
- Include rule-based styling examples and data processing workflows

index.html

@@ -6051,6 +6051,7 @@
           <button onclick="saveGeoJsonRoutes()" data-tip="Download routes data in GeoJSON format">routes</button>
           <button onclick="saveGeoJsonRivers()" data-tip="Download rivers data in GeoJSON format">rivers</button>
           <button onclick="saveGeoJsonMarkers()" data-tip="Download markers data in GeoJSON format">markers</button>
+          <button onclick="saveGeoJsonBurgs()" data-tip="Download burgs data in GeoJSON format">burgs</button>
         </div>
         <p>
           GeoJSON format is used in GIS tools such as QGIS. Check out