offsite-sync-backup + nfs-change-tracker: exclude /srv/nfs/anca-elements

The 771G under /srv/nfs/anca-elements is a downstream replica synced
FROM Synology (/volume1/Backup/Anca/Elements) by anca-elements-sync.sh.
The offsite-sync pipeline was copying it back to Synology under
/volume1/Backup/Viki/nfs/anca-elements, creating a self-duplicate
(~122G already partially copied during the last monthly full sync).

- nfs-change-tracker.service: drop anca-elements/ from inotify watch
  (incremental syncs no longer queue these paths)
- offsite-sync-backup.sh: --exclude='anca-elements/' on the monthly
  full rsync; grep -v on the incremental files-from list

Deployed to 192.168.1.127:/usr/local/bin/offsite-sync-backup +
/etc/systemd/system/nfs-change-tracker.service; service reloaded.

scripts/nfs-change-tracker.service

@@ -7,7 +7,7 @@ Type=simple
 ExecStart=/usr/bin/inotifywait -m -r \
     --format '%%w%%f' \
     -e create -e modify -e moved_to -e delete \
-    --exclude '(/\..*swp$|/\.nfs|/\.Trash|\.db-shm$|\.db-wal$|\.db-journal$|/stats/.*\.stat$)' \
+    --exclude '(/\..*swp$|/\.nfs|/\.Trash|\.db-shm$|\.db-wal$|\.db-journal$|/stats/.*\.stat$|^/srv/nfs/anca-elements/)' \
     /srv/nfs \
     /srv/nfs-ssd
 StandardOutput=append:/mnt/backup/.nfs-changes.log