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.

docs/CURRENT-STATE.md

@@ -584,7 +584,9 @@ pinning, first-position grace, source time and sea-surface placement are unchang
 
 Military flights also separate portable records and source acquisition from
 Cesium snapshot application. The metadata owner retains aviation feet, source
-fix times, sticky fields and partial-feed retention. Rendering retains ground
+fix times, sticky fields and partial-feed retention. A row without track or
+speed holds the last known value, as civil records do; a grounded row without
+speed reads 0. Rendering retains ground
 model ownership, motion history, military registration and tracking cleanup.
 
 Civil flights separate source acquisition, portable record reconciliation and