Keyring Controllers [Hardware]

Notion Epic:
https://www.notion.so/Share-the-network-transaction-and-keyring-controllers-between-both-products-9346f65b8f7f4b31887123a96b581d8f

The issue body only links to a Notion Epic, which is the first reference to review. That link should define the hardware keyring-controller scope and acceptance criteria; the issue itself does not name files, tests, entry points, or what completion looks like.

Written by the indexing model from the issue text.