reduce graphics memory and hidden render work

src/components/delayedPresence.test.mts

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+import assert from 'node:assert/strict';
+import test from 'node:test';
+import {
+  delayedPresenceReducer,
+  scheduleDelayedPresenceHide,
+} from './delayedPresence.ts';
+import {
+  EQ_GRAPH_UNMOUNT_DELAY_MS,
+  NOW_PLAYING_CLOSE_UNMOUNT_MS,
+} from './renderPresenceTiming.ts';
+
+const wait = (delayMs: number) => new Promise((resolve) => setTimeout(resolve, delayMs));
+
+test('Now Playing remains mounted through close timing, then releases', async () => {
+  let retained = false;
+  retained = delayedPresenceReducer(retained, 'show');
+  assert.equal(retained, true);
+  scheduleDelayedPresenceHide(NOW_PLAYING_CLOSE_UNMOUNT_MS, () => {
+    retained = delayedPresenceReducer(retained, 'hide');
+  });
+  await wait(NOW_PLAYING_CLOSE_UNMOUNT_MS - 20);
+  assert.equal(retained, true, 'surface must survive the close animation');
+  await wait(35);
+  assert.equal(retained, false);
+});
+
+test('rapid close/reopen cancels the pending release', async () => {
+  let retained = delayedPresenceReducer(false, 'show');
+  const cancelHide = scheduleDelayedPresenceHide(20, () => {
+    retained = delayedPresenceReducer(retained, 'hide');
+  });
+  cancelHide();
+  retained = delayedPresenceReducer(retained, 'show');
+  await wait(30);
+  assert.equal(retained, true);
+});
+
+test('background drop releases immediately and foreground open restores', () => {
+  let retained = delayedPresenceReducer(false, 'show');
+  retained = delayedPresenceReducer(retained, 'drop');
+  assert.equal(retained, false);
+  retained = delayedPresenceReducer(retained, 'show');
+  assert.equal(retained, true);
+});
+
+test('focused EQ surface remains through the tab settling window', async () => {
+  assert.equal(EQ_GRAPH_UNMOUNT_DELAY_MS, 190);
+  let retained = delayedPresenceReducer(false, 'show');
+  scheduleDelayedPresenceHide(EQ_GRAPH_UNMOUNT_DELAY_MS, () => {
+    retained = delayedPresenceReducer(retained, 'hide');
+  });
+  await wait(EQ_GRAPH_UNMOUNT_DELAY_MS - 20);
+  assert.equal(retained, true);
+  await wait(35);
+  assert.equal(retained, false);
+});