fix(military): hold the last track and speed when a poll omits them

MilitaryFlightRecords coerced a missing course to 0 (`courseDeg || 0`)
and a missing speed to 0 (`speedMps ?? 0`) before stickyNumber, so the
hold-last-known-good merge never ran. When an adsb.lol row arrived
without `track` or `gs`, the aircraft's icon swung to north and the
position history got a 0 kt / 0 degree fix, so dead reckoning stopped
or turned it north. The civil FlightRecords holds the last value for
the same input.

Pass the raw values to stickyNumber, with 0 as the fallback only until a
value is known, as before. A grounded row without a speed still reads
0, so a parked aircraft doesn't coast at its landing speed.

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+- Military aircraft keep their last heading and speed when an adsb.lol row omits
+  `track` or `gs`, instead of turning north and stopping; a grounded row without
+  a speed still reads 0.
+
 - Add Barcelona's bike share to the GBFS registry: Bicing (543 stations, the
   city's PBSC system) and AMBici (237 e-bike stations across the metropolitan
   area, run by nextbike). Both are keyless GBFS 2.3 feeds listed in