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/engine-coupling-baseline.json

@@ -1,16 +1,16 @@
 {
   "metrics": {
-    "cesiumLayerRendererLines": 1636,
-    "navaraLayerRendererLines": 6953,
-    "cesiumImportFiles": 65,
-    "viewerLines": 1901,
-    "navaraKindChecks": 12,
+    "cesiumLayerRendererLines": 1011,
+    "navaraLayerRendererLines": 4832,
+    "cesiumImportFiles": 53,
+    "viewerLines": 1745,
+    "navaraKindChecks": 9,
     "engineSniffCalls": 14,
-    "engineExtensionReads": 26,
-    "groundEffectPasses": 7,
+    "engineExtensionReads": 19,
+    "groundEffectPasses": 5,
     "cesiumSdkLoads": 6,
-    "screenSpaceHandlerFiles": 10,
-    "engineNameLines": 133
+    "screenSpaceHandlerFiles": 8,
+    "engineNameLines": 108
   },
-  "measuredAt": "after the radio, transit and CCTV displays; one engine.extensions read is CCTV's meshes seam, 2026-11-07"
+  "measuredAt": "after the ground layers (earthquakes, air quality, GNSS, perimeters, drone airspace, FIRMS, GhostMaps, cyclones, cables), 2026-11-07"
 }