Draw nine layers' fills through engine.ground, one display each

Earthquakes, air quality, GNSS Integrity, fire perimeters, Prohibited &
Restricted Airspace, Active Fires, S2 GhostMaps, cyclone advisories and
submarine cables each have one render/display.js on the globe contract;
their render/cesium* and render/navara* files go. Their discs, cells,
polygons and corridors are engine.ground sets, so on Navara they come from
the one ground screen pass with exact colours instead of nine hand-written
classification passes and lit SDK vector layers. Cesium's look stays the
reference:

- Earthquake and air-quality discs have no outline (Cesium drew none on
  clamped ellipses); earthquake discs can now be picked on Navara too.
- Perimeters, drone zones and GhostMaps polygons outline their outer
  ring only, as Cesium did.
- GNSS cells stay out of the pick pass; cyclone cones, tracks and centres
  are culled by a port of Cesium's horizon occluder.
- Submarine cables are one ground corridor set, as Cesium batched them;
  landing points, tips and stems are movers and lines.
- FIRMS glows are a sprite set and its cells a ground set. The far-zoom
  heat raster, which no primitive draws yet, sits behind one seam,
  render/heatField.js, with a Cesium and a Navara backend.

The shared Navara ground helpers that only these layers used go
(navaraGroundCells, the cell and ground geometry, the zone renderers), as
does the ground prototype script.

Coupling: layer renderer lines fall from 1636/6953 to 1011/4832
(Cesium/Navara), Navara ground passes from 7 to 5, Cesium-importing files
from 65 to 53, engine.extensions reads from 26 to 19.

scripts/check-import-directions.mjs

@@ -34,6 +34,10 @@ const navaraPackage = /^(?:(?:three|postprocessing)(?:\/|$)|@navaramap\/)/;
 // cesium only in render/cesium*.js, three and Navara only in
 // render/navara*.js. The list grows with each layer moved onto renderers.
 const RENDERED_LAYER_DIRS = [
+  'src/layers/droneAirspace/',
+  'src/layers/cyclones/',
+  'src/layers/ghostMaps/',
+  'src/layers/submarineCables/',
   'src/layers/alpr/',
   'src/layers/cctv/',
   'src/layers/transit/',