v2.12.0 — per-vhost access log viewer (A82)

A82: view any site's access log from the Logs page. The Logs page now has a "Site access log" picker listing your managed domains — selecting one tails (or fixed-string searches) that site's Caddy access log. The broker derives the path from the domain and re-checks it stays under the web log directory, so it is read-only and path-safe. System logs remain available via "— system logs —". App/error logs for Octane/PM2/Docker sites stay on the Docker logs page and the runtime status.