docs(core): [SITE-04] document component lifecycle and selector contracts

packages/artplayer-vitepress/docs/en/component/contextmenu.md

@@ -7,11 +7,12 @@
 | `disable` | `Boolean`           | Whether to disable the component     |
 | `name`    | `String`            | Unique component name for CSS class  |
 | `index`   | `Number`            | Component index for display priority |
-| `html`    | `String`, `Element` | DOM element of the component         |
+| `html`    | `String`, `Element`, `Number` | DOM element of the component         |
 | `style`   | `Object`            | Component style object               |
 | `click`   | `Function`          | Component click event                |
 | `mounted` | `Function`          | Triggered after component mount      |
-| `tooltip` | `String`            | Tooltip text for the component       |
+| `beforeUnmount` | `Function` | Hook before explicit remove/update |
+| `tooltip` | `String`, `Number`            | Tooltip text for the component       |
 
 ## Creation
 
@@ -125,4 +126,23 @@ art.on('ready', () => {
         })
     }, 3000);
 });
-```
+```
+
+## Menu management and lifecycle {#contextmenu-contract}
+
+See [shared component behavior](./layers#component-contract) for options, callbacks, return values, name conflicts and update/cleanup rules. The parent is template.$contextmenu; the manager name is contextmenu, with art-contextmenu and art-contextmenu-NAME item classes. show/toggle control the whole menu, not individual availability. Clicking a custom entry does not automatically close it; set art.contextmenu.show = false in your callback when needed.
+
+Desktop initialization installs built-in/configured entries and handles the context-menu event, keyboard, outside clicks and player blur. Mobile does not automatically run that initialization. Direct add can still register entries, but does not install the complete desktop context-menu flow. Use add/update/remove rather than repeating initialization to refresh entries.
+
+## TypeScript menu example
+
+```ts
+import Artplayer from 'artplayer/runtime';
+
+const art = new Artplayer({ container: '#player', url: '/video.mp4' });
+const menu: HTMLDivElement | undefined = art.contextmenu.add({
+    name: 'custom-menu', html: 'Close menu',
+    click() { this.contextmenu.show = false; },
+});
+if (menu) art.contextmenu.remove('custom-menu');
+```