Account for encrypted reasoning for auto compaction (#7113)

- The total token used returned from the api doesn't account for the
reasoning items before the assistant message
- Account for those for auto compaction
- Add the encrypted reasoning effort in the common tests utils
- Add a test to make sure it works as expected

codex-rs/Cargo.lock

@@ -1777,6 +1777,7 @@ version = "0.0.0"
 dependencies = [
  "anyhow",
  "assert_cmd",
+ "base64",
  "codex-core",
  "codex-protocol",
  "notify",