See who a recipe book is shared with, and stop sharing with someone

A list of the people who have a shared recipe book, and a way to take access away from one of them. Decision — 29 October 2026: Not planned. Decide against a participant list or individual-member revocation under key-link sharing: no member registry or per-person encryption key exists. Existing destructive account/primary-owner rotation purges relay owners and resets the account; that is distinct from selectively revoking a person and cannot recall downloaded copies. Do not advertise it as safe per-book revocation. The concrete warning is implemented in ShareBookDialog.tsx (a012583): share only with trusted people, links can be forwarded, individual access cannot be revoked.