* Initial plan
* Fix ADSB altitude integer overflow and add on-ground indicator
- Fix display overflow: use to_string_dec_int (signed) instead of
to_string_dec_uint (unsigned) for altitude display - per ICAO Annex 10
Vol IV 3.1.2.6.5.4, altitude = 25N-1000 can be as low as -1000ft
- Remove incorrect altitude clamp (altitude < 0 => 0) in DF 0/4/20 decoder
- Add on_ground flag to AircraftRecentEntry; set from TC 5-8 (surface
position) messages, cleared on TC 9-22 (airborne position) messages
- Display 'GND' in altitude column when aircraft is on ground
- Clear altitude to 0 when on_ground is set to prevent stale data in map
color calculation
Closes#3274
* Revert on-ground indicator; keep only the overflow and clamp fixes
Remove on_ground field, TC 5-8 handling, and "GND" display per review
feedback. Only keep the two minimal bug fixes:
- Signed altitude display (to_string_dec_int vs to_string_dec_uint)
- Remove erroneous altitude < 0 clamp; update comment to show the math
Copilot
483a100100