Feat: setup testing infrastructure

[ThisIsMissEm]

This changes src/index.tsx to not directly start the application, but instead to just create it, such that it can be required in different scenarios.

The entrypoint bin/server.ts is now used instead, and I've also added support for specifying the LISTEN_HOST (this may currently be backwards incompatible, as Hollo may have been listening on all interfaces originally).

There is an issue here in that we can't currently migrate the "test" database because drizzle-kit doesn't seem to accept any way to pass the correct env-file to use, the documentation seems to suggest using dotenv instead: https://orm.drizzle.team/docs/get-started/postgresql-new

We also currently use the Flydrive-js Disk interface, but for testing we'd want to switch to DriveManager which supports fakes: https://flydrive.dev/docs/drive_manager (this means we don't actually need to test against s3 or fs disks), for now, I'm using the fs driver and creating a directory before running the tests. Issue #115 addresses this.

[ThisIsMissEm]

We probably need to use dotenv in drizzle config in order to support migrating the test database in development, in CI the need for dotenv is bypassed because we're setting the DATABASE_URL as an environment variable.

[ThisIsMissEm]

@dahlia as test / check does what check used to do from build / check you'll want to adjust the branch restrictions (though I have made it correctly use biome ci with the github reporter.

[ThisIsMissEm]

This workflow is identical to the build.yaml workflow that's been removed, the only change is that we're not running this on pull requests.

[ThisIsMissEm]

We can probably delete the conditionals here on if it's a push.

[dahlia]

Thanks a lot! I left a few review comments.

[ThisIsMissEm]

@dahlia I'm not sure we even need check in this workflow, apart from the last step about something for tags and changes to be released?

[dahlia]

Everything looks good to me. Thank you!