Page modification safety property in the simulator

We had some nasty bugs where page was marked dirty after they were modified:

https://github.com/tursodatabase/turso/pull/4231

https://github.com/tursodatabase/turso/pull/4232

Let's extend the simulator to detect these types of cases. For example, we can calculate a page content hash when we load the page from disk. We can then in add_dirty verify that the hash is unchanged; otherwise someone changed the page without first marking it as dirty. We can make the simulator use the hashes to verify things like rollback safety.