Analogous to fractional delegation. Same registry as a vault + MBR post-condition pattern.

Updates the requirements on [eslint](https://github.com/eslint/eslint) to permit the latest version.
- [Release notes](https://github.com/eslint/eslint/releases)
- [Commits](https://github.com/eslint/eslint/compare/v10.8.0...v10.8.1)

---
updated-dependencies:
- dependency-name: eslint
  dependency-version: 10.8.1
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>

Bumps [@typescript-eslint/parser](https://github.com/typescript-eslint/typescript-eslint/tree/HEAD/packages/parser) from 8.67.0 to 8.66.0.
- [Release notes](https://github.com/typescript-eslint/typescript-eslint/releases)
- [Changelog](https://github.com/typescript-eslint/typescript-eslint/blob/main/packages/parser/CHANGELOG.md)
- [Commits](https://github.com/typescript-eslint/typescript-eslint/commits/v8.66.0/packages/parser)

---
updated-dependencies:
- dependency-name: "@typescript-eslint/parser"
  dependency-version: 8.66.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

- `makeVoteTxns` now names the frac registry app and its `instances` box on every vote, top-up or not, given the state-conditional inner call on `checkNeedMBR`.

- Ref-slot padding goes `numEscrows * 5 + 20` -> `+ 21` for the extra box.

- `extraFee` is deliberately unchanged. Both MBR hops pay their own fee, so the voter's group fee is invariant to whether the top-up fires.

- New `instanceBoxName` in util/boxes.ts, deriving prefix and key encoding from the ARC-56 spec rather than hardcoding 'i' + uint16.

- Test coverage includes regression-like cases for the whole MBR top-up flow.