chore: import upstream snapshot with attribution

packages/core/src/v3/input-streams-api.ts

@@ -0,0 +1,7 @@
+// Split module-level variable definition into separate files to allow
+// tree-shaking on each api instance.
+import { InputStreamsAPI } from "./inputStreams/index.js";
+
+export const inputStreams = InputStreamsAPI.getInstance();
+
+export * from "./inputStreams/types.js";