Has anyone built a mobile app on top of SQLite that can work offline, but then sync to a server when it gets connectivity? It feels like this could be built with a similar approach to this distributed SQLite, you'd "just" need more robust conflict handling.

I haven't personally but typically people use a CRDT-based approach like vlcn[1] or Mycelite[2].

[1]: https://github.com/vlcn-io/cr-sqlite

[2]: https://github.com/mycelial/mycelite