perf: debounce activity updates

tabby-core/src/components/baseTab.component.ts

@@ -1,4 +1,4 @@
-import { Observable, Subject, distinctUntilChanged } from 'rxjs'
+import { Observable, Subject, distinctUntilChanged, debounceTime } from 'rxjs'
 import { EmbeddedViewRef, ViewContainerRef, ViewRef } from '@angular/core'
 import { RecoveryToken } from '../api/tabRecovery'
 import { BaseComponent } from './base.component'
@@ -71,7 +71,7 @@ export abstract class BaseTabComponent extends BaseComponent {
     get blurred$ (): Observable<void> { return this.blurred }
     get titleChange$ (): Observable<string> { return this.titleChange.pipe(distinctUntilChanged()) }
     get progress$ (): Observable<number|null> { return this.progress.pipe(distinctUntilChanged()) }
-    get activity$ (): Observable<boolean> { return this.activity }
+    get activity$ (): Observable<boolean> { return this.activity.pipe(debounceTime(500)) }
     get destroyed$ (): Observable<void> { return this.destroyed }
     get recoveryStateChangedHint$ (): Observable<void> { return this.recoveryStateChangedHint }