chore: update Nginx proxy configuration to use variable resolution and bind start script to all interfaces

nginx.conf

@@ -29,16 +29,13 @@ http {
     log_format clean ' $request_method $uri $status';
     access_log /var/log/nginx/access.log clean if=$loggable;
 
-    upstream backend {
-        server app:3000;
-    }
-
     server {
         listen 80;
         resolver 127.0.0.11 valid=5s ipv6=off;
+        set $backend http://app:3000;
 
         location / {
-            proxy_pass http://backend;
+            proxy_pass $backend;
             proxy_set_header Host $host;
             proxy_set_header X-Real-IP $remote_addr;
             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

package.json

@@ -6,7 +6,7 @@
     "dev:t": "PORT=4000 bun --bun next dev --turbopack",
     "dev": "PORT=4000 bun --bun next dev",
     "build": "next build",
-    "start": "next start -H $HOSTNAME",
+    "start": "next start -H 0.0.0.0",
     "lint": "eslint",
     "up": "docker compose up -d --build",
     "logs": "docker compose logs -f erika",