I've already spun up claude to make a POC for this.

I like gerrit, but the server is such a pain to handle (java plus FS). PG would be the only server side component required, though you could have an optional review server that would act like a PG client as well.

The FUSE would be extremely nice for CI/CD for instant cloning with a local resource cache, which is much harder to do with a FS based git.