/**
 * Narrow `DriveClient` interface — just enough of the Drive v3 API surface
 * for the fetcher to call. Lets unit tests inject a fake at the transport
 * seam instead of mocking `@googleapis/drive` internals.
 *
 * The shape mirrors the real `drive_v3.Drive` client where it matters:
 * `files.get`, `files.export`, `files.list`. Anything else stays unused.
 */
export {};
