## Summary
-
## Test plan
- [ ] `cargo test` passes
- [ ] `cargo clippy --all-targets -- -D warnings` clean
- [ ] `cargo fmt --check` clean
- [ ]
## Breaking change
- [ ] No breaking change
- [ ] Yes — described below
## Related
- Closes #
- RFC:
## Reviewer checklist
- [ ] No `unwrap` / `expect` / `panic!` / `todo!` / `unreachable!` in library code
- [ ] No raw `==` on signature, hash, or key bytes (use `subtle::ConstantTimeEq`)
- [ ] If touching crypto / signature / audit chain: `crypto-auditor` agent has reviewed
- [ ] If adding a new `pub` item: doc comment + at least one example
- [ ] If changing on-disk format: an RFC exists, format version is bumped