Export a bank (async)

Submit an async export of a bank as a transfer ZIP archive. Three flags choose what the archive carries: include_data (documents, facts, observations, attachments and their bytes, the curation archive, the operations log and the maintenance queues), include_bank_config (bank config, mental models and their history, knowledge pages), include_bank_config (the bank's config overrides, directives and webhooks) and include_history (audit_log, llm_requests). Embeddings and database ids are never carried — importing re-embeds with the target bank's model and re-resolves entities, so an archive moves between instances configured with different embedding models. Returns an operation_id; poll GET /v1/default/banks/{bank_id}/operations/{operation_id}, then fetch the archive from the download_url in its result_metadata. Pass document_id to export specific documents instead of the whole bank (a document subset carries no bank-level sections).