Merge main; keep inline panels polling while their host reports them hidden

Main now has #1282, which pauses periodic layer polling in a hidden page
with its own catch-up and listener cleanup, so this PR drops its duplicate
lifecycle.js change and test in favor of main's.

Review fixes:
- data.js passes panelAwareVisibility(document) (new in app/embed.js) as
  the lifecycle's visibility target, so an inline panel whose host reports
  it hidden keeps polling. The HUD's 250 ms readout follows the same
  document.hidden && !isEmbeddedInline() rule as tools.js.
- Tests: embed.test.mjs (layers poll in an inline panel reported hidden,
  pause without the flag) and hudPageVisibility.test.mjs (HUD readout).
  Both use mock timers and clean up in finally.
- changelog.d/1344-inline-panel-visibility.md and a note in
  docs/CURRENT-STATE.md.

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

src/app/data.js

@@ -1,6 +1,7 @@
 import { LayerLifecycle } from '../data/lifecycle.js';
 import { LayerPresentation } from './layerPresentation.js';
 import { createCyberSonarScene } from '../cyberSonarScene.js';
+import { panelAwareVisibility } from './embed.js';
 /** Register the application layer catalog before allowing state restoration. */
 export function createApplicationData({
   scene: { viewer, mapStackController },
@@ -13,16 +14,10 @@ export function createApplicationData({
   // Initialize data layer manager
   const dataManager = new LayerLifecycle(viewer, {
     allowQaRegistration,
+    // A panel's host may report it hidden while it is on screen; its layers
+    // keep polling (see keepPanelRendering in embed.js).
+    visibilityTarget: panelAwareVisibility(document),
     getSourceAvailability: catalog?.getSourceAvailability,
-    // Polled layers skip refreshes while the tab is hidden and catch up
-    // once when it is shown again.
-    pageVisibility: {
-      isHidden: () => document.visibilityState === 'hidden',
-      subscribe(callback) {
-        document.addEventListener('visibilitychange', callback);
-        return () => document.removeEventListener('visibilitychange', callback);
-      },
-    },
   });
   defer(async () => {
     await dataManager.destroyAll();

src/app/embed.js

@@ -45,6 +45,28 @@ export function isEmbeddedInline() {
   return globalThis.GEV_EMBED_INLINE === true;
 }
 
+/**
+ * `doc`'s visibility for work that pauses in a hidden page. A panel's host
+ * may report it hidden while it is on screen (see keepPanelRendering), so an
+ * inline panel always reads as visible.
+ */
+export function panelAwareVisibility(doc = globalThis.document) {
+  const hidden = () =>
+    (doc.hidden === true || doc.visibilityState === 'hidden') &&
+    !isEmbeddedInline();
+  return {
+    get hidden() {
+      return hidden();
+    },
+    get visibilityState() {
+      return hidden() ? 'hidden' : 'visible';
+    },
+    addEventListener: (type, listener) => doc.addEventListener(type, listener),
+    removeEventListener: (type, listener) =>
+      doc.removeEventListener(type, listener),
+  };
+}
+
 // A panel keeps drawing at about this rate when its host stops animation
 // frames; see keepPanelRendering.
 const PANEL_FRAME_MS = 33;

src/app/embed.test.mjs

@@ -5,7 +5,9 @@ import {
   installViews,
   isEmbedded,
   keepPanelRendering,
+  panelAwareVisibility,
 } from './embed.js';
+import { LayerLifecycle } from '../data/lifecycle.js';
 import { createView } from '../view/index.js';
 
 const fakeViewer = () => {
@@ -211,6 +213,60 @@ test('an app loaded inline into a panel page talks through its own window', asyn
   }
 });
 
+test('polled layers keep refreshing in an inline panel its host reports hidden', async (t) => {
+  const listeners = new Set();
+  const doc = {
+    hidden: true,
+    visibilityState: 'hidden',
+    addEventListener: (_type, fn) => listeners.add(fn),
+    removeEventListener: (_type, fn) => listeners.delete(fn),
+  };
+  const settle = async () => {
+    for (let i = 0; i < 3; i++) await Promise.resolve();
+  };
+  t.mock.timers.enable({ apis: ['setInterval', 'Date'], now: 1000 });
+  let updates = 0;
+  const manager = new LayerLifecycle(
+    {},
+    { visibilityTarget: panelAwareVisibility(doc) },
+  );
+  manager.register({
+    id: 'flights',
+    name: 'flights',
+    icon: '',
+    source: 'test',
+    updateInterval: 1000,
+    async init() {},
+    enable() {},
+    disable() {},
+    async update() {
+      updates++;
+      await Promise.resolve();
+    },
+    getStats: () => ({ count: 0, lastUpdate: null }),
+  });
+  globalThis.GEV_EMBED_INLINE = true;
+  try {
+    await manager.setEnabled('flights', true);
+    await settle();
+    const enabled = updates;
+    t.mock.timers.tick(1000);
+    await settle();
+    t.mock.timers.tick(1000);
+    await settle();
+    assert.equal(updates, enabled + 2, 'the panel keeps polling');
+
+    delete globalThis.GEV_EMBED_INLINE;
+    t.mock.timers.tick(1000);
+    await settle();
+    assert.equal(updates, enabled + 2, 'outside a panel a hidden page pauses');
+  } finally {
+    delete globalThis.GEV_EMBED_INLINE;
+    await manager.destroyAll();
+  }
+  assert.equal(listeners.size, 0);
+});
+
 test('annotations in a link are drawn after it restores, embedded or not', async () => {
   const { calls, run } = recorder();
   const an = encodeURIComponent(