## Summary
Describe the change and motivation.
## Checklist
- [ ] Tests added/updated
- [ ] `cargo test` passes locally
- [ ] Docs updated
- [ ] Existing docs updated where behavior changed
- [ ] New doc added under `docs/` if introducing a new area
- [ ] Linked from `docs/README.md`
## Links / Design notes
Add design notes, code pointers, or diagrams if helpful.