Evaluate migrating to protobuf-es

[tstirrat15]

https://github.com/bufbuild/protobuf-es

It's actively maintained (unlike protobuf-ts) and also has nicer ergonomics around oneOf types, which we have plenty of.

[tstirrat15]

Apparently the maintainer of protobuf-ts is a maintainer on protobuf-es as well.

[tstirrat15]

It'd use https://www.npmjs.com/package/@connectrpc/connect-node on the backend. It seems like it'd be pretty good DX. I'm a little concerned about what happens if Buf (the company) disappears.