Remove the RepoISO integration; keep generic support for shares of other services

RepoISO now manages the NAS itself, so nasmon no longer polls it (settings field, dashboard card,
menu link and repoiso:* alerts are gone). Drop-in SMB includes, read-only listing and keeping
smbd/nfs-server running for other software's shares stay.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -11,9 +11,9 @@ share management from the UI.
 * Service: `systemctl status nasmon` / `journalctl -u nasmon -f`
 * JSON API: `/api/status`, `/api/history?hours=24`, `/api/disks/<serial>/history?days=30`
 
-Integrates with RepoISO on the same host: shares of other services
-(`/etc/samba/smb.conf.d`, `/etc/exports.d`) are included and kept running,
-and RepoISO health is shown on the dashboard and alerted on.
+Shares of other software on the same host (`/etc/samba/smb.conf.d/*.conf`,
+`/etc/exports.d/*.exports`) are included into the generated config, listed
+read-only and keep smbd / nfs-server running.
 
 No authentication — designed for a LAN-only NAS (the `/shares` page can
 create SMB/NFS users and exports, so keep it off the public internet).