fix(auto-thumbnail): [PKG-AUTO-THUMB-13] ignore registration after destroy

test/browser/README.md

@@ -529,6 +529,14 @@ The first immediate-pixel WebKit failure remains in the refactor evidence.
 This is native desktop media playback, not physical audibility or full devices.
 `document-site.spec.js` also checks generated guide links and Run Code parameters.
 
+## Auto-thumbnail delayed registration
+
+Auto-thumbnail's `auto-thumbnail-registration.spec.js` separately checks direct
+registrars delivered after real core destruction. It keeps the Promise/name
+contract, records zero subscriptions and verifies a late metadata event cannot
+allocate a hidden native video. It uses the source/artifact/installed resolver;
+this boundary test does not replace successful decoding or first-frame tests.
+
 ## VTT Thumbnail documentation examples
 
 yarn test:browser document-vtt.spec.js document-site.spec.js --workers=1 validates both generated guides and their Run Code destinations after yarn build:docs. The guide test requires the original demo verbatim, preserves the original demo video and substitutes local VTT/SVG resources, and inspects actual preview screenshot pixels with pngjs. It covers red/blue crops from real mouse hover, inclusive endpoint selection via public setBar with a MouseEvent, a gap, destroy and a late event on both cores. It loads local dist explicitly and records its hash; this does not replace the verified installed-artifact suite, physical touch tests or full playback acceptance.

test/browser/auto-thumbnail-registration.spec.js

@@ -0,0 +1,39 @@
+import { hash } from '../../refactor/scripts/releases.mjs'
+import { autoThumbnailCandidate } from '../helpers/auto-thumbnail.js'
+import { expect, test } from './fixtures.js'
+
+const implementation = await autoThumbnailCandidate()
+for (const core of ['published', 'candidate']) {
+  test(`Auto-thumbnail delayed factory installation stays inert after ${core} core destruction`, async ({ page }, testInfo) => {
+    await page.goto(`/test/player.html?core=${core}`)
+    await page.addScriptTag({ content: implementation.code })
+    const evidence = await page.evaluate(async () => {
+      window.createPlayer('/test/pattern.mp4')
+      const art = window.art
+      const install = window.artplayerPluginAutoThumbnail({ width: 80, number: 1 })
+      art.destroy()
+      const subscriptions = []
+      const on = art.on
+      art.on = function (name, callback) {
+        subscriptions.push(name)
+        return on.call(this, name, callback)
+      }
+      try {
+        const pending = install(art)
+        const asynchronous = typeof pending.then === 'function'
+        const result = await pending
+        art.emit('video:loadedmetadata')
+        const videos = document.querySelectorAll('video').length
+        const canvases = document.querySelectorAll('canvas').length
+        // Clean up the deliberate regression probe even when the old bundle leaks.
+        art.emit('destroy')
+        return { destroyed: art.isDestroy, asynchronous, result, subscriptions, videos, canvases }
+      }
+      finally {
+        art.on = on
+      }
+    })
+    await testInfo.attach('auto-thumbnail-late-registration', { contentType: 'application/json', body: JSON.stringify({ core, sha256: hash(implementation.code), provenance: implementation.provenance, ...evidence }) })
+    expect(evidence).toEqual({ destroyed: true, asynchronous: true, result: { name: 'artplayerPluginAutoThumbnail' }, subscriptions: [], videos: 0, canvases: 0 })
+  })
+}