NEW_CONTACT adverts were always logged as newly discovered, even for
nodes heard many times before. Check the tracking DB (get_tracked_contact_row)
and the live device contact list (is_contact_on_device) to classify the
advert, log "known" vs "new" accordingly, and skip the
new_contact_discovered audit entry for contacts that are already known.
Also dedup the is_currently_tracked device-contact lookups onto the shared
is_contact_on_device() helper.
Behavior preserved: repeaters remain database-only, device-mode companion
adds are still left to the firmware, and no per-advert device round-trip is
introduced.
agessaman
75f9fae374