feat(fires): far zoom shows a Snap Map-style heatmap instead of heat squares

The global and regional LOD bands drape the heat raster on the active
imagery host and draw no rectangle entities; the 2/1 degree aggregation now
only feeds the "N FIRES" cards, whose accent is the strongest fire's FRP
color. Markers below ~750 km hide the heatmap, as do disable and destroy.
A stale raster is rebuilt immediately on first paint and with a 150 ms
trailing debounce afterwards, so a slider drag does not re-encode on every
step. The shell hands the layer its imagery host, so the heatmap follows
globe and 3D-tiles map stacks.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/layers/firms/queries.js

@@ -9,7 +9,7 @@ import {
   sliderPositionForFrp,
 } from '../../data/firmsIntensity.js';
 import { formatNumber, t } from '../../i18n/index.js';
-import { REFRESH_INTERVAL_MS } from './policy.js';
+import { LOD_LEVELS, REFRESH_INTERVAL_MS } from './policy.js';
 
 /** Slider resolution: whole-percent positions along the log axis. */
 const SLIDER_STEPS = 1000;
@@ -309,6 +309,19 @@ export function createQueries({
       return result;
     },
 
+    /** Test seam: render one named LOD band against a near-global view. */
+    _renderLodForTest(lodId) {
+      const lod = LOD_LEVELS.find((level) => level.id === lodId);
+      if (lod.mode === 'detections')
+        components.rendering.renderDetections(lod, null);
+      else components.rendering.renderHeat(lod, null);
+    },
+
+    /** Test seam: entities drawn by the layer's data source. */
+    _entityCountForTest() {
+      return layerState._dataSource?.entities?.values?.length ?? 0;
+    },
+
     /** Test seam that binds the production click path and indexes. */
     _bindInteractionForTest(viewer, fires = []) {
       layerState._viewer = viewer;