Stop Navara's memory growth on engine switches, hide polygon zones reliably, and drop the Cesium camera rig

- Navara 0.2.1 never frees pick batch ids, and the mover banks rebuilt
  their instanced meshes on each attach, leaking about 260 KiB of
  WebAssembly memory per switch. A per-view pool hands released ids back
  out; the long soak now asserts native growth of at most 32 KiB per switch.
- Navara 0.2.1 sometimes drops the first show:false update on a new
  vector layer, so a zone turned off right after a switch back stayed
  drawn. Polygon displays hide by deleting their layers and rebuild them
  when shown.
- Camera verbs drive both engines through the globe contract; the Cesium
  viewer rig and the tests of states it can no longer reach are gone.
- Flights and military tracking share src/layers/aircraft/tracking.js.
- The geo import scenario reads movers only where the engine has them.
- Add the Navara section to docs/CURRENT-STATE.md and a changelog fragment.

scripts/package-boundaries.json

@@ -1352,6 +1352,7 @@
       "src/layers/flights/ingestion.js",
       "src/layers/flights/lifecycle.js",
       "src/layers/aircraft/sceneBinding.js",
+      "src/layers/aircraft/tracking.js",
       "src/layers/flights/motion.js",
       "src/layers/flights/policy.js",
       "src/layers/flights/queries.js",
@@ -1419,6 +1420,7 @@
       "src/layers/military/index.js",
       "src/layers/military/ingestion.js",
       "src/layers/aircraft/sceneBinding.js",
+      "src/layers/aircraft/tracking.js",
       "src/layers/military/lifecycle.js",
       "src/layers/military/motion.js",
       "src/layers/military/policy.js",
@@ -2650,6 +2652,7 @@
       "src/layers/flights/ingestion.js",
       "src/layers/flights/lifecycle.js",
       "src/layers/aircraft/sceneBinding.js",
+      "src/layers/aircraft/tracking.js",
       "src/layers/flights/motion.js",
       "src/layers/flights/policy.js",
       "src/layers/flights/queries.js",
@@ -3414,6 +3417,7 @@
       "src/globe/follow.js",
       "src/globe/lines.js",
       "src/globe/navara/movers/pickIds.js",
+      "src/globe/navara/movers/batchIds.js",
       "src/globe/movers.js",
       "src/globe/cesium/follow.js",
       "src/globe/cpuPicks.js",
@@ -3789,6 +3793,7 @@
       "src/layers/flights/ingestion.js",
       "src/layers/flights/lifecycle.js",
       "src/layers/aircraft/sceneBinding.js",
+      "src/layers/aircraft/tracking.js",
       "src/layers/flights/motion.js",
       "src/layers/flights/policy.js",
       "src/layers/flights/queries.js",