Note these two types were identical, so it seems clear to standardize on the one in `codex_protocol` and eliminate the `Into` stuff. --- [//]: # (BEGIN SAPLING FOOTER) Stack created with [Sapling](https://sapling-scm.com). Best reviewed with [ReviewStack](https://reviewstack.dev/openai/codex/pull/5218). * #5222 * __->__ #5218