build: add Navara for the experimental engine

Pins @navaramap/three and @navaramap/three-default-plugin 0.2.1 with
their peers three 0.185.1 and postprocessing 6.39.4 (mapillary-js keeps
its own nested three 0.134). The dev server leaves the Navara packages
and their wasm workers out of dependency pre-bundling so wasm-bindgen
resolves its .wasm next to the package. Nothing imports Navara yet: the
Cesium-mode main chunk is byte-identical (2,837,992 bytes, same hash).

build/vite.js

@@ -85,6 +85,18 @@ export function createBrowserViteConfig({
         // Loaded on demand when the first street-level image opens.
         'mapillary-js',
       ],
+      // Navara's wasm-bindgen glue loads new URL('x_bg.wasm', import.meta.url)
+      // and its workers by URL; both must resolve next to the package's own
+      // files, not inside .vite/deps. Dev server only: the experimental
+      // Navara engine is a dynamic import outside the Cesium-mode bundle.
+      exclude: [
+        '@navaramap/three',
+        '@navaramap/three-default-plugin',
+        '@navaramap/engine',
+        '@navaramap/engine-api',
+        '@navaramap/engine-worker',
+        '@navaramap/engine-font-worker',
+      ],
     },
     server: {
       host: host || 'localhost',