feat: add optional CDN URL configuration for static assets in Vite

frontend/vite.config.ts

@@ -29,7 +29,14 @@ export default defineConfig(({ mode }) => {
     "0.0.1"
   ).replaceAll(".", "-");
 
+  // Optional CDN URL for static assets (e.g., https://cdn.example.com)
+  // When set, all static assets will be served from this URL instead of the same origin.
+  // This is useful for serving assets from a CDN subdomain while keeping API calls on the main domain.
+  // If not set, assets are served from the same origin (backward compatible).
+  const cdnUrl = env.VITE_CDN_URL || "";
+
   return {
+    base: cdnUrl || "/",
     server: {
       allowedHosts,
       host: true,