fix(fires): keep retained heat hidden when reenabling an empty filter

Add a lifecycle regression and register it in the format scope.

src/layers/firms/heatVisibility.test.mjs

@@ -0,0 +1,44 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { createLifecycle } from './lifecycle.js';
+
+test('reenabling an empty filtered layer never reveals the retained pre-filter heat raster', async () => {
+  let shown = false;
+  const noop = () => {};
+  const layerState = {
+    _enabled: false,
+    _viewer: {},
+    _dataSource: {},
+    _fires: [],
+    _loading: true,
+    _pickIndexById: new Map(),
+    _heatImagery: {
+      setShow(v) {
+        shown = v;
+      },
+    },
+  };
+  const lifecycle = createLifecycle({
+    layerState,
+    services: {
+      picking: { registerPickOwner: noop, unregisterPickOwner: noop },
+      sprites: { restoreSpriteOrderOnEnable: noop },
+      context: { clearSelectedEntityContextForLayer: noop },
+    },
+    config: { id: 'local-firms', overlayHost: { setVisible: noop } },
+    components: {
+      rendering: { applyHandoffFade: noop },
+      viewport: { installLodWatcher: noop, installMoveEndWatcher: noop },
+      selection: { installClickHandler: noop },
+    },
+  });
+  await lifecycle.methods.enable(layerState._viewer);
+  assert.equal(
+    shown,
+    false,
+    'empty current set must keep the old raster hidden while refresh is pending',
+  );
+  layerState._fires = [{ frp: null, confidence: null }];
+  await lifecycle.methods.enable(layerState._viewer);
+  assert.equal(shown, true, 'nonempty sets still resume their raster');
+});

src/layers/firms/lifecycle.js

@@ -54,7 +54,8 @@ export function createLifecycle({
         layerState._billboards.show = true;
       }
       overlayHost.setVisible(FIRMS_OVERLAY_SOURCE_ID, true);
-      layerState._heatImagery?.setShow(true);
+      // A filter can leave an old raster cached while the current set is empty.
+      layerState._heatImagery?.setShow(layerState._fires.length > 0);
       // The camera can have crossed the hand-off while the layer was off.
       components.rendering.applyHandoffFade(true);
       components.viewport.installLodWatcher();