feat(ui): toggle rendered frame rate with backtick

src/ui/applicationShell.js

@@ -1,3 +1,4 @@
+import { createFrameRateMonitor } from './frameRateMonitor.js';
 import { createStateChannel } from '../app/stateChannel.js';
 import { setSplitFlapText } from '../splitFlap.js';
 import { UiLifetime } from './uiLifetime.js';
@@ -1389,6 +1390,11 @@ export class StyleManager {
       setScopeMaskFeather,
     } = this.services;
     this._applicationShortcuts?.destroy();
+    this._frameRateMonitor?.destroy();
+    this._frameRateMonitor = createFrameRateMonitor({
+      viewer: this.viewer,
+      documentRef: document,
+    });
     this._applicationShortcuts = bindApplicationShortcuts({
       documentRef: document,
       searchInput: this._locationSearch,
@@ -5293,6 +5299,7 @@ export class StyleManager {
     this._panelLayout.destroy();
     this._applicationShortcuts?.destroy();
     this._displayControls?.destroy();
+    this._frameRateMonitor?.destroy();
     this._mapSourceControls?.destroy();
     this._clearLayersControl?.destroy();
     this._locationControls?.destroy();