perf(models): aircraft models skip Cesium's dynamic environment map (#1366)

Skip per-aircraft dynamic environment maps while retaining default model lighting.

Contribution by @quanticsoul4772.

src/data/aircraftModelLighting.js

@@ -0,0 +1,17 @@
+/**
+ * Lighting options shared by every aircraft 3D model (Flights, Military
+ * Flights, Local ADS-B).
+ *
+ * Cesium gives each Model a dynamic environment map: it renders the sky around
+ * the model and reads the result back from the GPU (`readPixels`) to light it,
+ * when the model is first placed and again when it moves more than 1 km, when
+ * the scene's atmosphere settings change, or every scene hour under sunlight
+ * lighting. Aircraft models take 94% of their surface from the class colour
+ * (`colorBlendAmount`), so that lighting contributes little; without it they
+ * are lit from Cesium's default spherical harmonics. Measured 2026-10-24
+ * (Intel Arc, Google 3D, ~150 models in the scene): GPU per frame at rest
+ * 14.3-14.8 -> 12.1-12.5 ms.
+ */
+export const AIRCRAFT_ENVIRONMENT_MAP_OPTIONS = Object.freeze({
+  enabled: false,
+});