Test layers on one engine and share selection and shader helpers

Layer display tests no longer re-check Cesium primitives in every layer:
they run on the fake engine, and one Cesium translation check per ground
kind lives in the Cesium engine's ground tests. Their harnesses are shared,
and the fake-engine, Cesium-engine and flights tests that repeated the
contract suite are gone, 340 tests in all.

The press-travel measurement is shared by the selection dispatcher and
CCTV, which loses its ScreenSpaceEventHandler shim and world-click module.
ALPR, installations and bikeshare share one selection keeper and selected
marker write. Layers with their own click rules keep their handlers.

Navara's pulse is a class like the ground pass, the ground and imagery
passes share the surface uniforms, and the colour, log-depth and occlusion
GLSL lives in one chunk module, each caller keeping its depth bias. The
ground suite runs inside the contract suite (--only=ground:), and fixture
and script names say what they test.

Behaviour is unchanged on both engines.

scripts/format-scope.json

@@ -1212,6 +1212,7 @@
   "src/testSupport/cockpitEngine.mjs",
   "src/layers/aircraft/render/contract.js",
   "src/layers/shared/color.test.mjs",
+  "src/layers/shared/selectionKeeper.js",
   "src/layers/shared/color.js",
   "src/layers/shared/viewRectangle.js",
   "src/layers/military/render/display.js",
@@ -1222,7 +1223,6 @@
   "src/layers/vessels/renderer.test.mjs",
   "src/layers/vessels/testFixtures.mjs",
   "src/layers/shared/render/engineView.js",
-  "src/globe/navara/ground/effect.js",
   "src/layers/shared/render/moverBank.js",
   "src/layers/shared/render/imageAtlas.js",
   "src/layers/bikeshare/presentation.js",
@@ -1233,8 +1233,8 @@
   "src/layers/cctv/lifecycle.test.mjs",
   "src/layers/cctv/projectionMedia.test.mjs",
   "src/layers/cctv/ingestion.test.mjs",
-  "scripts/fixtures/w2/alpr.mjs",
-  "scripts/fixtures/w2/cctv.mjs",
+  "scripts/fixtures/layers/alpr.mjs",
+  "scripts/fixtures/layers/cctv.mjs",
   "src/layers/radio/screenClusters.js",
   "src/layers/radio/screenClusters.test.mjs",
   "src/globe/cesium/mapScene.js",
@@ -1258,7 +1258,7 @@
   "src/globe/cesium/testing/cameraViewer.mjs",
   "src/app/globeEngine.js",
   "src/app/globeEngine.test.mjs",
-  "scripts/fixtures/w2/transit.mjs",
+  "scripts/fixtures/layers/transit.mjs",
   "src/layers/localAdsb/render/display.js",
   "src/layers/localAdsb/renderer.test.mjs",
   "build/navaraAssets.js",
@@ -1381,16 +1381,16 @@
   "src/globe/navara/movers/frameCamera.test.mjs",
   "src/layers/localAdsb/qaDrawn.js",
   "src/layers/localAdsb/qaDrawn.test.mjs",
-  "src/tooling/w1RuntimeEvidence.test.mjs",
+  "src/tooling/browserRuntimeEvidence.test.mjs",
   "src/layers/firms/rectangle.js",
   "src/layers/firms/rectangle.test.mjs",
   "src/layers/firms/viewport.test.mjs",
-  "scripts/fixtures/w2/firms.mjs",
+  "scripts/fixtures/layers/firms.mjs",
   "src/layers/firms/lifecycle.test.mjs",
-  "scripts/fixtures/w2/radio.mjs",
+  "scripts/fixtures/layers/radio.mjs",
   "scripts/qa-map-policy.mjs",
   "scripts/qa-map-policy.test.mjs",
-  "scripts/qa-w2-imagery.mjs",
+  "scripts/qa-imagery-contract.mjs",
   "src/globe/navara/postSamplingPass.test.mjs",
   "src/globe/navara/emptySceneRender.test.mjs",
   "src/data/firmsIntensity.js",
@@ -1579,7 +1579,6 @@
   "src/globe/navara/ground/pack.js",
   "src/globe/navara/ground/pack.test.mjs",
   "src/globe/navara/ground/pass.js",
-  "scripts/qa-ground-suite.mjs",
   "docs/GLOBE-PRIMITIVES.md",
   "src/layers/airQuality/render/display.js",
   "src/layers/airQuality/render/display.test.mjs",