Mobile device integration testing

patience looks exactly like an idea I wrote down a while back, I think it'll work well if support for integration testing of mobile-based matrix apps is also added.

I see [Appetize](https://appetize.io/) mentioned in the readme, however, I think a locally-hostable alternative should also be considered.

Start with the repository README and its existing integration-testing setup, including the documented Appetize workflow. Determine the required scope for mobile Matrix client testing and evaluate a locally hostable alternative; this issue is complete only when the project has an agreed implementation path and working mobile integration tests.

Written by the indexing model from the issue text.