Rotate API keys without downtime using the 24-hour grace period.
POST /api/auth/api-keys/{key_id}/rotate
Authorization: Bearer {jwt_token}
// Response
{
"new_key": "nxs_test_abc123...",
"old_key_prefix": "nxs_test_old...",
"old_key_expires": "2026-04-12T...",
"message": "New key created. Old key valid for 24 hours."
}