feat(radio): render stations and clusters on Navara

Preserve native clustering, selection and direct-action playback through renderer ports. Record both-engine dev/preview, legacy, contract, shell and build evidence with remaining W2 limits.

scripts/check-import-directions.mjs

@@ -34,6 +34,7 @@ const navaraPackage = /^(?:(?:three|postprocessing)(?:\/|$)|@navaramap\/)/;
 // engine in their renderers: cesium only in render/cesium*.js, three and
 // Navara only in render/navara*.js. The list grows with each moved layer.
 const RENDERED_LAYER_DIRS = [
+  'src/layers/radio/',
   'src/layers/bikeshare/',
   'src/layers/earthquakes/',
   'src/layers/firms/',