CLI: maybe the formats thing is too strict

When running any new sync stuff, we check openfn.yaml for the formats of the repo

By default project files are saved to yaml

But we're a bit dogmatic about this. If I change the type to json, suddenly the workspace won't see anything.

That's because we check the file extension defined in the config to find relevant state files.

It's quite annoying if I want to switch format for any reason - there's no migration path, and things like checkout and merge just break.

Options:

1. Provide a command to convert the repo from one format to another. like open project config formats.project json. But that's quite awkward and it's hard to change many things at once
2. Treat the config as an OUTPUT format, not an input one. That means we can still read all yaml and json files in the projects folder (maybe subject to ignore rules in #1119). One problem here is if I change format, the old files still stay on disk.

Tricky one really. This is mostly a developer problem - I'm sure 95% of users will just use the default yaml formats (because they'll be nice, friendly, readable AND lightning-compatible)

Start by tracing how new sync operations read formats from openfn.yaml and locate relevant state files in the projects folder. Compare the proposed conversion command with treating the configured format as an output format, including the effects on checkout, merge, and existing files. Done requires a decided migration or discovery behavior, not just an implementation choice.