libadsb-reader 0.1.46

- Adds immutable RAM collection for standing-data flight routes.
- Both `flight` and `callsign` columns become lookup keys, so one DB record can
  produce two collection entries.
- Duplicate keys preserve the previous SQL priority: source priority,
  reference_date DESC, id DESC.
- adsb_standing_has_flight() and route enrichment now use RAM collection lookup.
- Aircraft RAM collection and 0.1.45 output coalescer remain unchanged.
