Flight Log Stays Live Across LOS → BLOS Handovers

Fixes a freeze where the Flight Log and package queue stopped updating after an aircraft lost line of sight and failed over to satellite. Horizon UI now keeps polling through link changes and drone handovers, whether the operator subscribed to BLOS manually or the failover happened automatically.

The Flight Log and package queue are also cleared when no aircraft is engaged, rather than carrying stale entries into the next session.

Clearer Plan-Upload Labels

An empty plan upload — the MAVLink way of clearing a Geofence or Rally Points plan — now appears in the Flight Log as Geofence Clear / Rally Clear instead of Geofence Upload: 0 items.

Athena Waypoint Sync

Horizon UI now sends the MISSION_CURRENT acknowledgement three times after a waypoint change, so the Athena ground control application reliably registers the active waypoint.