Load the layer displays lazily and rebase the main-chunk budget

Every layer display was imported statically from the manifest, so all of
them sat in the Cesium-mode main chunk. They are re-exported from one
module, src/app/layers/displays.js, which the manifest loads with one
import() before the catalog is built, on every engine; rendererFor stays
synchronous after that. One chunk beats per-family chunks here: every
start loads every display, and split chunks compress worse. CCTV's world
click gesture moves out of its display, which the app imported only for
it. Tests that build layers without the application await the loads.

Keyless, gzip-9: the main chunk falls from 2,113,641 to 2,066,560
bytes, below the 2,090,274 of the merge with main this branch carries.
A cold Cesium start loads about 7 KB more JS in total over four requests,
with the same time to a ready page. The budget's baseline moves to the
new size; it had never absorbed main's own growth.

scripts/package-boundaries.json

@@ -3447,6 +3447,7 @@
       "src/globe/navara/followGestures.js",
       "src/app/layers/directory.js",
       "src/app/layers/renderers.js",
+      "src/app/layers/displays.js",
       "src/layers/aircraft/render/display.js",
       "src/layers/flights/render/display.js",
       "src/layers/military/render/display.js",
@@ -3551,6 +3552,7 @@
       "src/layers/cctv/render/cesiumMeshes.js",
       "src/layers/cctv/render/meshes.js",
       "src/layers/cctv/render/display.js",
+      "src/layers/cctv/worldClick.js",
       "src/layers/transit/render/display.js",
       "src/layers/earthquakes/render/display.js",
       "src/layers/airQuality/render/display.js",
@@ -4229,6 +4231,7 @@
       "src/globe/cesium/follow.js",
       "src/app/layers/directory.js",
       "src/app/layers/renderers.js",
+      "src/app/layers/displays.js",
       "src/layers/aircraft/render/display.js",
       "src/data/selectionDispatcher.js",
       "src/layers/shared/color.js",
@@ -4293,6 +4296,7 @@
       "src/layers/cctv/render/cesiumMeshes.js",
       "src/layers/cctv/render/meshes.js",
       "src/layers/cctv/render/display.js",
+      "src/layers/cctv/worldClick.js",
       "src/layers/transit/render/display.js",
       "src/layers/earthquakes/render/display.js",
       "src/layers/airQuality/render/display.js",