feat(auto-thumbnail): [PKG-AUTO-THUMB-08] add compatible runtime type entry

packages/artplayer-plugin-auto-thumbnail/README.md

@@ -9,3 +9,49 @@ Auto thumbnail plugin for ArtPlayer
 ## License
 
 MIT © Harvey Zhao
+
+## TypeScript
+
+The root and `/legacy` entries retain the declarations published in 1.1.0,
+including the historical synchronous result type. The implementation actually
+returns a Promise when registering the plugin. For accurate types, opt into
+`/runtime`, which uses the same JavaScript implementation:
+
+```ts
+import Artplayer from 'artplayer'
+import autoThumbnail from 'artplayer-plugin-auto-thumbnail/runtime'
+import type { Option, Result } from 'artplayer-plugin-auto-thumbnail/runtime'
+
+const option: Option = { width: 160, number: 100, scale: 1 }
+const art = new Artplayer({
+  container: '#player',
+  url: '/video.mp4',
+  plugins: [autoThumbnail(option)],
+})
+```
+
+The registrar has type `(art: Artplayer) => Promise<Result>`. It resolves with
+`{ name: 'artplayerPluginAutoThumbnail' }` after subscribing to player events,
+before extraction completes. Generated sheets arrive progressively through the
+player's thumbnails configuration. Awaiting registration does not wait for them.
+The options object is required; use `{}` for defaults. `height` is accepted by
+the runtime type for historical callers but remains ignored: the video aspect
+ratio determines sheet height. Numeric strings retain their old JavaScript
+coercion behavior but are not advertised as numeric TypeScript options.
+
+The runtime entry supports default ESM imports and CommonJS
+`import autoThumbnail = require('artplayer-plugin-auto-thumbnail/runtime')`.
+It exports the `Option`, `Result`, and `Factory` types. The factory has no
+`.default` self alias and the result has no extraction-completion or destroy API.
+Node10 resolution uses `typesVersions`; modern resolution uses separate ESM/CJS
+declarations. The old root's NodeNext namespace behavior is preserved; `/runtime`
+provides a direct default-import type without changing that old declaration.
+
+Versions 1.0.x used `export =` declarations and advertised `height` instead of
+`number`; 1.1.0 had already changed these types. This refactor retains the actual
+1.1.0 root declaration rather than introducing another conflicting root shape.
+Consumers needing the older ignored `height` option can use `/runtime`.
+
+See [ARCHITECTURE.md](ARCHITECTURE.md) for module ownership, tests, and remaining
+browser extraction limitations. This type entry does not resolve the documented
+Windows WebKit first-frame issue.