I'd like to suggest Fossil SCM[1]. Your content (text, images etc.) is stored in a SQLite database [@] which is great! SQLite is a recommended storage format[2] for datasets according to US Library of Congress. Also, the SQLite developers pledge[3] to support it atleast until 2050.

[1] https://fossil-scm.org

[2] https://sqlite.org/locrsf.html

[3] https://sqlite.org/lts.html

[@] a single file, not a bunch of files in a directory