fix(military): read a GNSS-sourced vertical rate when no baro rate is sent

readsb reports an aircraft's vertical rate as geom_rate instead of baro_rate
when its source is GNSS. The military normaliser read only baro_rate, so about
one in six live /v2/mil contacts had a null vertical rate in analyst and
tracked-aircraft data. Fall back to geom_rate, as the adsb.lol flights
fallback already does; a sent baro_rate still wins.

docs/CURRENT-STATE.md

@@ -1058,7 +1058,8 @@ The tracked-aircraft descriptor both flight layers hand to the cockpit carries
 `verticalRate` and military records as `verticalRateMps`; the query seam maps both to
 one name, so `resolveTrackedAircraftInfo` returns a single shape for either layer. The
 rate is reported, never derived: a blank poll keeps the last transmitted value and an
-absent rate stays null rather than reading as level flight.
+absent rate stays null rather than reading as level flight. A military readsb row
+without `baro_rate` reports its GNSS rate as `geom_rate`, which is used instead.
 
 ## Transponder emergency highlighting