test(vtt-thumbnail): [PKG-VTT-THUMB-04] verify historical module forms and type conflicts

refactor/fixtures/consumers/vtt-thumbnail-export-alternatives.ts

@@ -0,0 +1,7 @@
+import type { Factory } from 'artplayer-plugin-vtt-thumbnail'
+
+declare const replacement: Factory
+const required: Factory & { default: Factory } = replacement
+const optional: Factory & { default?: Factory } = replacement
+optional.default({})
+void required