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## What

<!-- The change, in a sentence or two. Name the Hyperpart(s) affected. -->

## Why

<!-- The problem or gap. Screenshots/GIFs for anything visual. -->

## Checks

- [ ] `python build.py && python -m pytest tests/` passes locally
- [ ] New/changed classes have CSS rules (incl. JS-assigned classNames)
- [ ] New `hx-*` affordances have declared `Exchange` contracts
- [ ] Interactive changes considered under touch (`pointer: coarse`)