fix(cockpit): radar contacts stay where the vessel layer draws them

The vessel layer draws other ships at their last AIS fix and does not
advance them, so dead-reckoning radar contacts moved the mismatch from own
ship to everyone else: a 15 kn ferry reported 90 s ago showed ~700 m ahead
of the ship out of the window. Own ship stays centred where the camera
rides; contacts go back to their last fixes, and the query drops the extra
reach and candidates (which could also cut the nearest ship in a crowd).

docs/CURRENT-STATE.md

@@ -1591,9 +1591,9 @@ from the caret. The bridge radar
 shows nearby AIS ships heading-up and opens at 3 NM
 (`DEFAULT_RADAR_RANGE_NM` in `src/cockpitRadar.js`); its range button steps
 3, 6, 12 and 24 NM and the chosen range is kept across bridges. Own ship
-sits where the camera rides, and every contact's last fix is dead-reckoned
-along its course over ground to the same moment (`deadReckonRadarContacts`),
-so the scope matches the view out of the window. Contact
+sits where the camera rides (its fix dead-reckoned) and contacts at their
+last fixes, where the vessel layer draws them, so the scope matches the view
+out of the window. Contact
 Previous/Next and Live Signals aircraft handoffs are refused on the bridge and
 the Contact card stays hidden. Exit returns the camera to the vessel's map view
 through the layer's own focus. Tracking an aircraft or losing the vessel