Lighter basemap (Positron) + Fireside HQ POI marker

- Basemap switched from dark-matter to Positron — light grey, minimal,
  higher contrast for the cost-centre coloured markers.
- HQ POI: red dot + soft halo + 'Fireside Group HQ' label at
  -1.24089, 36.72880. Layered above vehicles so it stays visible when
  vehicles park there.
- Flipped vehicle plate-label colours to dark text + white halo for
  readability on the light map (was light-on-dark).

web/fleet-core.js

@@ -105,7 +105,7 @@ export function initMap(elementId, opts = {}) {
   const center = opts.center || [36.8172, -1.2864]; // Nairobi
   const zoom = opts.zoom ?? 7;
   const styleUrl = opts.styleUrl
-    || 'https://basemaps.cartocdn.com/gl/dark-matter-gl-style/style.json';
+    || 'https://basemaps.cartocdn.com/gl/positron-gl-style/style.json';
 
   // eslint-disable-next-line no-undef
   const map = new maplibregl.Map({
@@ -186,6 +186,8 @@ export function initMap(elementId, opts = {}) {
       },
     });
 
+    _addHqPoi(map);
+
     map.addLayer({
       id: 'vehicles-label',
       type: 'symbol',
@@ -209,8 +211,9 @@ export function initMap(elementId, opts = {}) {
         'text-letter-spacing': 0.04,
       },
       paint: {
-        'text-color': '#f1f5f9',
-        'text-halo-color': '#0f172a',
+        // Dark text + white halo reads cleanly on the Positron light basemap.
+        'text-color': '#0f172a',
+        'text-halo-color': '#ffffff',
         'text-halo-width': 2,
       },
     });
@@ -221,6 +224,70 @@ export function initMap(elementId, opts = {}) {
   return map;
 }
 
+/* ---------- POIs ---------- */
+
+const HQ_POI = {
+  name: 'Fireside Group HQ',
+  lng: 36.728803986483136,
+  lat: -1.2408926683427806,
+};
+
+function _addHqPoi(map) {
+  map.addSource('poi-source', {
+    type: 'geojson',
+    data: {
+      type: 'FeatureCollection',
+      features: [{
+        type: 'Feature',
+        properties: { name: HQ_POI.name, kind: 'hq' },
+        geometry: { type: 'Point', coordinates: [HQ_POI.lng, HQ_POI.lat] },
+      }],
+    },
+  });
+
+  map.addLayer({
+    id: 'poi-hq-halo',
+    type: 'circle',
+    source: 'poi-source',
+    paint: {
+      'circle-radius': ['interpolate', ['linear'], ['zoom'], 5, 5, 9, 9, 13, 16, 18, 26],
+      'circle-color': '#dc2626',
+      'circle-opacity': 0.20,
+    },
+  });
+  map.addLayer({
+    id: 'poi-hq-dot',
+    type: 'circle',
+    source: 'poi-source',
+    paint: {
+      'circle-radius': ['interpolate', ['linear'], ['zoom'], 5, 3, 9, 5, 13, 8, 18, 14],
+      'circle-color': '#dc2626',
+      'circle-stroke-color': '#ffffff',
+      'circle-stroke-width': 2,
+    },
+  });
+  map.addLayer({
+    id: 'poi-hq-label',
+    type: 'symbol',
+    source: 'poi-source',
+    minzoom: 9,
+    layout: {
+      'text-field': ['get', 'name'],
+      'text-font': ['Open Sans Bold', 'Arial Unicode MS Bold'],
+      'text-size': ['interpolate', ['linear'], ['zoom'], 9, 10, 13, 12, 17, 15],
+      'text-offset': [0, 1.4],
+      'text-anchor': 'top',
+      'text-allow-overlap': false,
+      'text-letter-spacing': 0.04,
+    },
+    paint: {
+      'text-color': '#7f1d1d',
+      'text-halo-color': '#ffffff',
+      'text-halo-width': 2,
+    },
+  });
+}
+
 /* ---------- hover popup ---------- */
 
 function _wireHoverPopup(map) {