refactor: unify media understanding pipeline

src/media-understanding/errors.ts

@@ -0,0 +1,17 @@
+export type MediaUnderstandingSkipReason = "maxBytes" | "timeout" | "unsupported" | "empty";
+
+export class MediaUnderstandingSkipError extends Error {
+  readonly reason: MediaUnderstandingSkipReason;
+
+  constructor(reason: MediaUnderstandingSkipReason, message: string) {
+    super(message);
+    this.reason = reason;
+    this.name = "MediaUnderstandingSkipError";
+  }
+}
+
+export function isMediaUnderstandingSkipError(
+  err: unknown,
+): err is MediaUnderstandingSkipError {
+  return err instanceof MediaUnderstandingSkipError;
+}