.ccms-checksums gets checksummed

[sldr-se]

Hello. Found an issue causing verification issues.

To the best of my understanding, the following happens (starting from a blank slate with an empty remote):

1. ccms push, generating the checksums of the content of ~/.claude, pushes that content, then uploads the checksums into the backup directory as .ccms-checksums
2. ccms pull, fetches the remote checksums, then fetches the content of the remote backup directory, including the .ccms-checksums file
3. ccms push, generates the checksums again, now including the downloaded .ccms-checksums file, pushes all that, then overwrites the just-pushed .ccms-checksums (pushed as part of the normal push) with the newly calculated checksums.
4. ccms pull fails, since it will get the remote checksums (which includes a checksum for .ccms-checksums, though no longer accurate since the last push), pull the contents, then verify the checksums and fail when .ccms-checksums doesn't match.

I think the root problem is that .ccms-checksums should be ignored during pull/push operations, since you otherwise get into the state where the checksums file contains a reference to itself, which gets all kinds of recursive.

There are a couple of solutions to this, but the simplest workaround I found is just adding .ccms-checksums to the ignore file, then potentially cleaning it up from the local/remote, depending on where in the process you are.