fix: dev proxy za frontend API pozive

U dev modu frontend sada koristi /api preko Astro/Vite proxy sloja prema backend servisu, umjesto direktnog gađanja localhost:8001 iz browsera.\n\nTime se uklanja ERR_CONNECTION_REFUSED u lokalnom Docker development okruženju.\n\nCo-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

docker-compose.dev.yml

@@ -34,7 +34,8 @@ services:
       - PUBLIC_HMR_HOST=localhost
       - PUBLIC_HMR_PROTOCOL=ws
       - PUBLIC_HMR_CLIENT_PORT=4321
-      - PUBLIC_API_URL=http://localhost:8001/api/
+      - PUBLIC_API_URL=http://localhost:4321/api/
+      - PUBLIC_API_PROXY_TARGET=http://backend:8000
   
   flower:
     container_name: 004erpflower