Add SVG layer snapshots for various components

- Added ruler layer snapshot with hidden display.
- Added scale bar layer snapshot with detailed structure and styling.
- Added temperature layer snapshot with opacity and stroke settings.
- Added terrain layer snapshot with ocean and land heights groups.
- Added vignette layer snapshot with mask and opacity settings.
- Added zones layer snapshot with specified opacity and stroke settings.

public/main.js

@@ -1227,8 +1227,12 @@ function showStatistics() {
     Cultures: ${pack.cultures.length - 1}`;
 
   mapId = Date.now(); // unique map id is it's creation date number
+  window.mapId = mapId; // expose for test automation
   mapHistory.push({seed, width: graphWidth, height: graphHeight, template: heightmap, created: mapId});
   INFO && console.info(stats);
+
+  // Dispatch event for test automation and external integrations
+  window.dispatchEvent(new CustomEvent('map:generated', { detail: { seed, mapId } }));
 }
 
 const regenerateMap = debounce(async function (options) {