Retrieve the status of a dubbing project and its dubbed videos. Status values: - uploading: The source video is still being uploaded/processed (only for projects created via sourceVideoUrl) - in_progress: Dubbing is in progress - complete: All dubbing is complete - error: An error occurred during dubbing Response varies by status: - UPLOADING: Returns only id and status - IN_PROGRESS/COMPLETE: Returns id, status, and dubbedAssets array - ERROR: Returns id, status, and errorCode Dubbed asset status: - IN_PROGRESS: Returns minimal data (id, language, status) - COMPLETE: Returns full data including download URLs - ERROR: Returns minimal data plus errorCode