feat: NASA Earthdata/GIBS Integration - Imagery-Switcher + FIRMS Layer

- imagery.js: WMTS-Support fuer NASA GIBS + 4 neue Quellen (MODIS Terra, VIIRS SNPP, GOES East/West)
- firms.js: Neuer VIIRS Thermal Anomalies Layer (375m, tagesaktuell, Braende/Industriewaerme)
- nightlights.js: NRT-Upgrade (dynamisches Datum statt hardcodiert 2024-01-01)
- index.html: Optgroups im Imagery-Select, FIRMS-Checkbox, Script-Tag
- app.js: FIRMS Toggle
- globe.css: dot-firms Farbe

Alle NASA-Daten kostenlos via GIBS WMTS, kein API-Key noetig.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

static/js/layers/nightlights.js

@@ -1,5 +1,6 @@
 /**
- * Nachtlicht-Layer: NASA VIIRS Black Marble Nighttime Lights.
+ * Nachtlicht-Layer: NASA VIIRS Black Marble Nighttime Lights (NRT).
+ * Verwendet tagesaktuelle Daten statt statischem Datum.
  */
 const NightlightsLayer = {
     _viewer: null,
@@ -8,20 +9,22 @@ const NightlightsLayer = {
     start: function(viewer) {
         if (this._layer) return;
         this._viewer = viewer;
+        // NRT-Daten brauchen ~12-24h Processing, daher Datum von gestern
+        var yesterday = new Date(Date.now() - 86400000).toISOString().slice(0, 10);
         this._layer = viewer.imageryLayers.addImageryProvider(
             new Cesium.WebMapTileServiceImageryProvider({
-                url: 'https://gibs.earthdata.nasa.gov/wmts/epsg4326/best/VIIRS_Black_Marble/default/2024-01-01/500m/{TileMatrix}/{TileRow}/{TileCol}.png',
-                layer: 'VIIRS_Black_Marble',
-                style: 'default',
-                tileMatrixSetID: '500m',
+                url: "https://gibs.earthdata.nasa.gov/wmts/epsg4326/best/VIIRS_Black_Marble/default/" + yesterday + "/500m/{TileMatrix}/{TileRow}/{TileCol}.png",
+                layer: "VIIRS_Black_Marble",
+                style: "default",
+                tileMatrixSetID: "500m",
                 tileMatrixLabels: [
-                    '0', '1', '2', '3', '4', '5', '6', '7', '8',
+                    "0", "1", "2", "3", "4", "5", "6", "7", "8",
                 ],
-                format: 'image/png',
+                format: "image/png",
                 tilingScheme: new Cesium.GeographicTilingScheme(),
                 tileWidth: 512,
                 tileHeight: 512,
-                credit: 'NASA VIIRS Black Marble',
+                credit: "NASA VIIRS Black Marble (NRT)",
             })
         );
         this._layer.alpha = 0.85;