The /admin/rate-limits/config routes were only mounted when the limiter
was running, and the limiter is only constructed at boot when
ratelimit.enabled is true. Disabling rate limiting from the UI and
restarting therefore 404'd the settings page permanently, with no way
to re-enable it without editing the database.
Mount the routes whenever the settings store exists and make the
handler tolerate a nil limiter: saves always persist, hot-reload is
skipped when nothing is running, and the PUT response reports
restart_required (enabling with no limiter built, or switching backend
on a running one). GET now exposes active/active_backend so the UI can
tell saved config apart from what the process is enforcing.
The settings page shows a persistent restart banner driven by that
server state, with the same restart flow as other settings pages via a
RestartServerButton extracted from SaveBar.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
