Api Arm Config Edit

Arm the config editor for one host: mint a short-lived edit token.

This is the deliberate, explicit action that gates config writes. The client calls it only after the user confirms they understand they're about to modify the security policy. The returned token must accompany the later write; a session cookie alone is not enough.

Rejects if the host is offline or lacks the self-edit tools in its allowlist — no point arming an editor that can't write.