feat(app): run gev on Navara behind ?engine=navara

The page's engine is ?engine=cesium|navara, else localStorage gev.engine,
else Cesium (src/app/engineChoice.js). Cesium mode is unchanged.

In Navara mode (src/app/navaraMode.js, loaded with import() only then,
and loading the Navara globe the same way) the scene builds the Navara
globe on the app container with no viewer; map stacks go through
engine.maps (Google 3D from the browser key, else Esri imagery); only the
shell's own data credits are registered. The layer catalog is empty and
the controls get empty layer stand-ins. The shell does not create its
viewer-bound parts (cockpit view, celestial ring, detection, tracked
readout, post-process stages); the tools install the render governor on
the engine, skip the director, annotations, drawing, imagery box, scope
mask, voice and embedded views, skip the first-run welcome, and show
"Experimental Navara engine: layers, cockpit, director and voice are
unavailable". window.__godsEyeView.viewer is null.

Navara's attribution card is kept clear of the location tray. A few
shell paths became null-safe for the missing viewer, layers or stages
without changing Cesium behaviour.

scripts/qa-engine-shell.mjs checks both modes headless: boot, viewer,
console errors, map drawn, search and fly, north/tilt/zoom/reset, orbit,
HUD, share link restore and map stacks.

scripts/package-boundaries.json

@@ -1760,6 +1760,18 @@
       "src/globe/cesium/render.js",
       "src/globe/cesium/surface.js",
       "src/globe/cesium/engineFromViewer.js",
+      "src/globe/navara/cameraMath.js",
+      "src/globe/navara/cameraModel.js",
+      "src/globe/navara/createNavaraEngine.js",
+      "src/globe/navara/credits.js",
+      "src/globe/navara/index.js",
+      "src/globe/navara/input.js",
+      "src/globe/navara/internals.js",
+      "src/globe/navara/maps.js",
+      "src/globe/navara/surface.js",
+      "src/globe/navara/viewOptions.js",
+      "src/app/engineChoice.js",
+      "src/app/navaraMode.js",
       "src/sources/sourceSlot.js",
       "src/app/sources.js",
       "src/app/startupChrome.js",
@@ -2525,7 +2537,11 @@
       "pbf",
       "satellite.js",
       "mapillary-js",
-      "@jtarrio/webrtlsdr"
+      "@jtarrio/webrtlsdr",
+      "@navaramap/three",
+      "@navaramap/three-default-plugin",
+      "three",
+      "postprocessing"
     ]
   },
   "application-catalog": {