fix: hardcode backend UUID in nginx proxy to prevent cross-app routing

frontend/nginx.conf

@@ -3,13 +3,13 @@ server {
     server_name localhost;
 
     location /api/ {
-        proxy_pass http://backend:5000;
+        proxy_pass http://hpegebuubw1mirg08rszhqzy:5000;
         proxy_set_header Host $host;
         proxy_set_header X-Real-IP $remote_addr;
     }
 
     location /uploads/ {
-        proxy_pass http://backend:5000;
+        proxy_pass http://hpegebuubw1mirg08rszhqzy:5000;
         proxy_set_header Host $host;
     }