feat(mapillary): catalog, layer state, sources, key setup and build wiring

MAPILLARY_CLIENT_TOKEN is a public client token and reaches the browser
through the explicit define block; ANTHROPIC_API_KEY stays server-side.
Both appear in POWER UP with links to create them.

Co-Authored-By: Claude Fable 5.1 <[email protected]>

server/standalone/vite.config.js

@@ -16,6 +16,7 @@ export default defineConfig(({ mode }) => {
     plugins: [...localProviderPlugins(), apiNotFoundPlugin()],
     googleApiKey: process.env.GOOGLE_MAPS_API_KEY,
     cesiumToken: process.env.CESIUM_ION_TOKEN,
+    mapillaryToken: process.env.MAPILLARY_CLIENT_TOKEN,
     host: process.env.HOST,
     port: process.env.PORT,
   });