update dockerfile to sync env

frontend/Dockerfile

@@ -9,6 +9,7 @@ COPY . .
 # COPY ./.env.example ./.env
 
 RUN bun install
+RUN bunx @sveltejs/kit sync
 
 RUN bun run build
 

frontend/src/routes/(test)/testenv/+page.svelte

@@ -1,5 +1,7 @@
 <script>
 	import { PUBLIC_SHORTENER_URL } from '$env/static/public'
+	import { env } from '$env/dynamic/public'
 </script>
 
 <div>{PUBLIC_SHORTENER_URL}</div>
+<div>Dynamic env: {env.PUBLIC_SHORTENER_URL}</div>