Remove CLI Input E-graph

[oflatt]

I propose we refactor the CLI so that it does not take an e-graph as input. Instead, users like egglog-experimental add to the e-graph produced by CLI (rather than giving the e-graph as input).

This would make it so that we can safely set proof mode in CLI before anything has mutated the e-graph.

[saulshanabrook]

Need this for proofs for correctness