Fix Wereldexport world map loading and tiles.

Self-host Leaflet locally, proxy map tiles through cockpit, set explicit map height, and invalidate size after init.

cockpit/static/js/export-intel.js

@@ -25,6 +25,7 @@ function exportIntelApp() {
     mapTypesSelected: [],
     mapHalalMode: false,
     mapHalalMin: 55,
+    mapError: '',
     halalTopMarkets: [],
     halalTopEntities: [],
     listFocusId: null,
@@ -322,6 +323,11 @@ function exportIntelApp() {
       var bundle = await fetch(url).then((r) => r.json());
       this.halalTopMarkets = (bundle.meta && bundle.meta.top_markets) || [];
       this.halalTopEntities = (bundle.meta && bundle.meta.top_halal_entities) || [];
+      if (!window.L || !window.ExportIntelMap) {
+        this.mapError = 'Kaart kon niet laden. Vernieuw de pagina (Ctrl+F5).';
+        return;
+      }
+      this.mapError = '';
       if (window.ExportIntelMap) {
         if (!document.getElementById('ei-map')) return;
         var self = this;