* docs(03-persistence): mention SQLite as an alternative backend
* Update README with persistence options and SQLite note
Clarify persistence options and mention SQLite as a potential upgrade for handling concurrent writers and richer queries.
* Revise persistence options in README.zh.md
Updated the section on persistence options to clarify the transition from file-based storage to database solutions like SQLite and Postgres.
* Fix typos and enhance clarity in README.md
Corrected spelling of 'Postgre' to 'Postgres' and improved clarity of the note about persistence.
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Co-authored-by: Zane Chen <99708452+czl9707@users.noreply.github.com>
