它只生成素材，不直接更新 `history.json`。最终摘要确认后再更新历史锚点，避免'从上次继续'读到半成品。

Fingerprint is a general purpose data integrity tool that uses cryptographic hashes to detect changes in files and directory trees. The fingerprint command scans a directory tree and generates a fingerprint file containing the names and cryptographic hashes of the files in the tree. This snapshot can be later used to generate a list of files that have been created, deleted or modified. If so much as a single bit in the file data has changed, Fingerprint will detect it.

Data integrity is a good thing. Constraining the values allowed by your application at the database-level, rather than at the application-level, is a more robust way of ensuring your data stays sane.

I haven't met anyone who makes this argument who then says that a one stop convenient, reliable, private and secure online learning environment can’t be achieved using common every day online systems