Keep tracked-entity state in Core records instead of on Cesium entities

Flights, military, satellites, installations, local ADS-B and ALPR hung
gevTrackedId, gevDisplayPosition, gevVisualPosition, gevSelectionOrigin and
gevLabelModel on the Cesium entities they draw, and the tracked readout,
follow camera, cockpit, share links and awareness read them back. They now
live in src/data/entityRecords.js, a Core-owned record per entity: layers
write entityRecord(entity), readers use readEntityRecord(entity). Nothing
changes on screen. This is the first slice of the renderer plan's state
mirror (P1).

The module is exported as ./data/entity-records so hosted code can read the
same records, and window.__godsEyeView.entityRecords gives the QA scripts
the same access from the page.

src/data/flights.test.mjs

@@ -28,6 +28,7 @@ import {
   destroyTrackedReadout,
   initTrackedReadout,
 } from './trackedReadout.js';
+import { readEntityRecord, withEntityRecord } from './entityRecords.js';
 
 test('share-Follow absence requires an accepted OpenSky snapshot', async () => {
   _setFlightTrackingRefreshOutcomeForTest({ status: 'source-unavailable' });
@@ -184,7 +185,7 @@ test('flights first update forwards caller cancellation into the feed request',
 test('nonempty OpenSky payload with zero usable rows cannot prove share target absence', async () => {
   _setTrackedFlightRefreshStateForTest({
     icao24: 'abc123',
-    entity: { gevLabelModel: { title: 'WARM', details: [] } },
+    entity: withEntityRecord({}, { labelModel: { title: 'WARM', details: [] } }),
     billboard: { show: false },
     billboardCollection: { show: true, remove() {} },
     viewer: { camera: { positionCartographic: null }, scene: {} },
@@ -317,7 +318,7 @@ test('a newly seen aircraft appears at its delayed position, not ahead of it', a
 
 test('flights poll refreshes tracked callsign/FL/kts and marks a missed poll STALE', async () => {
   const icao24 = 'a1b2c3';
-  const entity = { gevLabelModel: { title: 'OLD', details: [] } };
+  const entity = withEntityRecord({}, { labelModel: { title: 'OLD', details: [] } });
   const billboard = {
     position: Cesium.Cartesian3.fromDegrees(-97.7, 30.2, 9_000),
     color: Cesium.Color.WHITE,
@@ -388,13 +389,13 @@ test('flights poll refreshes tracked callsign/FL/kts and marks a missed poll STA
 
   try {
     await flightsLayer.update(viewer);
-    assert.equal(entity.gevLabelModel.title, 'DAL123');
-    assert.match(entity.gevLabelModel.details.join(' · '), /FL350/);
-    assert.match(entity.gevLabelModel.details.join(' · '), /486 kts/);
+    assert.equal(readEntityRecord(entity)?.labelModel.title, 'DAL123');
+    assert.match(readEntityRecord(entity)?.labelModel.details.join(' · '), /FL350/);
+    assert.match(readEntityRecord(entity)?.labelModel.details.join(' · '), /486 kts/);
 
     await flightsLayer.update(viewer);
     assert.match(
-      [entity.gevLabelModel.title, ...entity.gevLabelModel.details].join(' · '),
+      [readEntityRecord(entity)?.labelModel.title, ...readEntityRecord(entity)?.labelModel.details].join(' · '),
       /STALE/,
     );
   } finally {
@@ -527,7 +528,7 @@ test('real civil track path creates no native label and publishes every cached h
     assert.ok(
       entities.values.every((candidate) => candidate.label === undefined),
     );
-    assert.deepEqual(entity.gevLabelModel, {
+    assert.deepEqual(readEntityRecord(entity)?.labelModel, {
       title: 'N12345 · FL350 · 486 kts',
       details: ['TEST AIR · A320', 'AUS → LAX'],
       accent: '#39d0ff',
@@ -546,7 +547,7 @@ test('real civil track path creates no native label and publishes every cached h
       'user',
       'same-target selection upgrades durable authority',
     );
-    assert.equal(entity.gevSelectionOrigin, 'user');
+    assert.equal(readEntityRecord(entity)?.selectionOrigin, 'user');
     assert.equal(flightsLayer.refocusTrackedById('different-flight'), false);
     assert.equal(
       flightsLayer.refocusTrackedById(icao24, { origin: 'voice' }),
@@ -579,8 +580,8 @@ test('real civil track path creates no native label and publishes every cached h
     const entry = publication.entries[0];
     assert.equal(entry.protected, true);
     assert.equal(entry.paintLane, 'tracked');
-    assert.equal(entry.title, entity.gevLabelModel.title);
-    assert.deepEqual(entry.details, entity.gevLabelModel.details);
+    assert.equal(entry.title, readEntityRecord(entity)?.labelModel.title);
+    assert.deepEqual(entry.details, readEntityRecord(entity)?.labelModel.details);
 
     const display = entity.position.getValue(now);
     assert.ok(display, 'tracked position callback must seed its frame cache');
@@ -941,7 +942,7 @@ test('civil label chain: the awareness selection EVENT uses the canonical chain'
 });
 
 test('civil tracked readout: a callsign-less enriched contact reads as its registration', async () => {
-  const entity = { gevLabelModel: { title: 'OLD', details: [] } };
+  const entity = withEntityRecord({}, { labelModel: { title: 'OLD', details: [] } });
   seedLabelContact({ callsign: '  ', registration: ' N123AB ', tracked: true });
   _setTrackedFlightRefreshStateForTest({
     icao24: LABEL_ICAO,
@@ -981,9 +982,9 @@ test('civil tracked readout: a callsign-less enriched contact reads as its regis
       camera: { positionCartographic: null },
       scene: {},
     });
-    assert.match(entity.gevLabelModel.title, /^N123AB\b/);
+    assert.match(readEntityRecord(entity)?.labelModel.title, /^N123AB\b/);
     assert.doesNotMatch(
-      [entity.gevLabelModel.title, ...entity.gevLabelModel.details].join(' · '),
+      [readEntityRecord(entity)?.labelModel.title, ...readEntityRecord(entity)?.labelModel.details].join(' · '),
       /ae1fa4/,
     );
   } finally {