refactor(multiple-subtitles): [PKG-MULTI-SUB-04] expose compatible runtime type entry

packages/artplayer-plugin-multiple-subtitles/README.md

@@ -6,6 +6,29 @@ Multiple subtitles plugin for ArtPlayer
 
 [https://artplayer.org](https://artplayer.org/?libs=./uncompiled/artplayer-plugin-multiple-subtitles/index.js&example=multiple.subtitles)
 
+## TypeScript
+
+The root and `/legacy` type entries preserve historical parameter and return-type extraction.
+Registration has always been asynchronous. For accurate Promise and selection-method types,
+use the additive runtime entry, which loads the same implementation:
+
+```ts
+import multipleSubtitles from 'artplayer-plugin-multiple-subtitles/runtime'
+
+const register = multipleSubtitles({
+  subtitles: [{ url: '/subtitles/en.vtt', name: 'en' }],
+})
+// With an existing ArtPlayer instance:
+const result = await register(art)
+result.tracks(['en'])
+result.reset()
+```
+
+The option object is required; `{}` means no tracks. `tracks()` clears the selection;
+`reset()` restores all original tracks. Both methods return `void`. The existing `onParser`
+field remains declared for compatibility but is not invoked by the implementation.
+See [maintenance notes](ARCHITECTURE.md) for module responsibilities and validation commands.
+
 ## License
 
 MIT © Harvey Zhao