fix: use custom nginx.pid path to avoid permission error

frontend/nginx.global.conf

@@ -1,9 +1,7 @@
 # frontend/nginx.global.conf
 
-# Remove user directive to avoid warning
-# user nginx;
-
 worker_processes 1;
+pid /app/nginx.pid;  # ✅ Add this line to avoid /run/nginx.pid error
 
 events {
     worker_connections 1024;