Extract instance-owned civil-flight components

src/data/detectionRenderDemand.test.mjs

@@ -1,3 +1,4 @@
+import { readLayerSource } from '../testSupport/readLayerSource.mjs';
 // src/data/detectionRenderDemand.test.mjs
 //
 // Detection must not hold the render loop open — and must not drop work on the
@@ -427,7 +428,7 @@ test('the render-governor gate covers the parked case, with teeth on the painter
 // promptness goes with them, silently. This test is where that shows up.
 test('aircraft brackets stay prompt because the aircraft layers hold the render loop', async () => {
   for (const file of ['./flights.js', './militaryFlights.js']) {
-    const source = await readFile(new URL(file, import.meta.url), 'utf8');
+    const source = readLayerSource(new URL(file, import.meta.url));
     const enable = /\n  enable\([\s\S]*?\n  \},/.exec(source)?.[0];
     assert.ok(enable, `${file}: enable() is still identifiable`);
     assert.match(