fix(multiple-subtitles): [PKG-MULTI-SUB-04] preserve historical type shapes

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

@@ -8,7 +8,10 @@ Multiple subtitles plugin for ArtPlayer
 
 ## TypeScript
 
-The root and `/legacy` type entries preserve historical parameter and return-type extraction.
+The root and `/legacy` type entries preserve the latest published 1.2.0 function shape:
+a required `{ subtitles: TrackOption[] }` argument and a synchronous `{ name: 'multipleSubtitles' }`
+registration result. This includes parameter extraction and replacement-factory assignment in
+both directions; the root factory type has no required `.default` property.
 Registration has always been asynchronous. For accurate Promise and selection-method types,
 use the additive runtime entry, which loads the same implementation:
 
@@ -27,6 +30,36 @@ 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.
+
+### Earlier declarations and module resolution
+
+Versions 1.0.0 and 1.1.0 declared `export =`, whereas 1.2.0 declared a default export.
+The root follows 1.2.0 under the approved [type compatibility policy](../../refactor/type-compatibility-policy.md).
+For consumers migrating an earlier `import = require`, use the accurate runtime entry and
+await registration:
+
+```ts
+import type Artplayer from 'artplayer'
+import multipleSubtitles = require('artplayer-plugin-multiple-subtitles/runtime')
+
+async function registerSubtitles(art: Artplayer) {
+  const result = await multipleSubtitles({ subtitles: [] })(art)
+  result.reset()
+}
+```
+
+This `import = require` form works with classic Node resolution without `esModuleInterop`.
+The runtime default import in the first example requires that flag in classic CommonJS;
+NodeNext ESM and bundler resolution use its ESM declaration. Runtime types also expose the
+existing writable `.default` self alias. JavaScript entrypoints and valid historical
+`require('artplayer-plugin-multiple-subtitles').default(...)` calls remain supported.
+The old 1.0.0/1.1.0 declaration allowed calling the raw `require` object, but its shipped
+JavaScript did not; that mismatch is not a supported runtime contract.
+
+NodeNext ESM intentionally retains the 1.2.0 root declaration's module namespace shape
+(`import root from 'artplayer-plugin-multiple-subtitles'` exposes the declared factory as
+`root.default`). It does not silently become a callable default type. Prefer the `/runtime`
+default import for accurate native ESM calls; the same applies to `/legacy` declarations.
 See [maintenance notes](ARCHITECTURE.md) for module responsibilities and validation commands.
 
 ## License