Controlling dialogs and popovers with the Invoker Commands API

The Invoker Commands API introduces `command` and `commandfor` attributes to HTML buttons, enabling control of dialogs and popovers without JavaScript. Built-in commands include `show-modal`, `close`, and `request-close` for dialogs, plus `show-popover`, `hide-popover`, and `toggle-popover` for popovers. Custom commands prefixed with `--` allow developers to extend functionality beyond the built-in options. Available in Chrome 135+, Edge 135+, Opera 120+, Firefox 144+, and Safari Technology Preview, with a polyfill for older browsers.