cometbft v1.0 has many large changes, one of which is moving many of their packages into internal to reduce their API surface, as we did too. cometbft/cometbft#1484 (they also made a module of their e2e test code to reduce pollution of the main module go.mod, and carved out some submodules like api, so many of the same steps we took.).

The main consequence is that the internal/abci/cometbft/privval package requires a rewrite without a few now-internal cometbft packages (lib/...). This was copy/paste code to get a signer that was not file-based.

There are other very minor changes like eliminating use of their lib/os package, but that's simple since we have mostly avoided it and kept our use of cometbft imports very isolated to abci or cometbft packages.