fix(types): PKG-CHAPTER-04 preserve CJS ESM and legacy consumer contracts

test/types/language-value.ts

@@ -0,0 +1,10 @@
+import type { I18n } from 'artplayer'
+import french from 'artplayer/i18n/fr'
+
+const dictionary: NonNullable<I18n['en']> = french
+const close: string | undefined = french.Close
+// @ts-expect-error Translation values cannot be numbers.
+const numeric: number = french.Close
+// @ts-expect-error Language values do not have a permissive arbitrary-key index.
+const missing = french.notATranslation
+void [dictionary, close, numeric, missing]