refactor(dash): [PKG-DASH-04] migrate strict TypeScript and compatible declarations

test/types/dash-source.ts

@@ -0,0 +1,9 @@
+import type PublicFactory from 'artplayer-plugin-dash-control'
+import factory from '../../packages/artplayer-plugin-dash-control/src/index'
+
+const compatible: typeof PublicFactory = factory
+const implementation: typeof factory = compatible
+implementation({ quality: { getName: level => `${level.height}p` }, audio: { getName: track => track.lang || String(track.id) } })
+compatible()
+// @ts-expect-error Source and public declaration reject invalid formatter results.
+factory({ quality: { getName: () => 1 } })