feat: add SVG layer export bookmarklet with all-visible composite

Add export-svg-layers.js that extracts geographic/natural SVG layers
(landmass, coastline, lakes, ocean, ice, rivers, terrain) as standalone
SVGs with inlined styles, plus with-landmass background variants and a
combined all-visible-layers SVG. Output is a zip file via JSZip.

Author: barrulus

tools/geojson-exports/export-all.js

@@ -181,8 +181,9 @@
       .filter(function (m) { return m && !m.removed && m.x != null && m.y != null; })
       .map(function (m) {
         var props = { id: m.i, icon: m.icon || "", type: m.type || "" };
-        if (window.notes) {
-          var note = window.notes.find(function (n) { return n.id === "marker" + m.i; });
+        var notesArray = typeof notes !== "undefined" && Array.isArray(notes) ? notes : [];
+        if (notesArray.length) {
+          var note = notesArray.find(function (n) { return n.id === "marker" + m.i; });
           if (note) { props.name = note.name || ""; props.legend = note.legend || ""; }
         }
         return {

tools/geojson-exports/export-markers.js

@@ -42,9 +42,10 @@
     });
 
   // Also include notes for markers if available
-  if (window.notes) {
+  var notesArray = typeof notes !== "undefined" && Array.isArray(notes) ? notes : [];
+  if (notesArray.length) {
     features.forEach(function (f) {
-      var note = window.notes.find(function (n) {
+      var note = notesArray.find(function (n) {
         return n.id === "marker" + f.properties.id;
       });
       if (note) {