NightbreakServerLink
Connects this server to a Nightbreak account without copying a token.
The server asks nightbreak.io for a code, prints a link carrying it, and polls with a secret only it holds. When the account owner approves the code in a browser, the next poll returns the account token, which is saved exactly as /nightbreaklogin <token> saves it. The protocol is described in the account manager's docs/plans/2026-10-26-server-link-design.md.
One link is active per shaded copy; starting another replaces it.