What is Zone.js, how does it monkey-patch browser APIs, and how do you build a Zoneless Angular application?

import { bootstrapApplication } from '@angular/platform-browser';
import { provideExperimentalZonelessChangeDetection, Component, signal } from '@angular/core';

@Component({
  selector: 'app-root',
  standalone: true,
  template: '<button (click)="inc()">Count: {{ count() }}</button>'
})
class AppComponent {
  count = signal(0);
  inc() { this.count.update(c => c + 1); }
}

bootstrapApplication(AppComponent, {
  providers: [
    provideExperimentalZonelessChangeDetection()
  ]
});