Update deployment files: fix nginx proxy, update SQL schema, consolidate to single images tar

SerpentRace_Frontend/nginx.conf

@@ -22,7 +22,7 @@ server {
 
     # API proxy to backend
     location /api/ {
-        proxy_pass http://backend:3000/;
+        proxy_pass http://backend:3000;
         proxy_http_version 1.1;
         proxy_set_header Upgrade $http_upgrade;
         proxy_set_header Connection 'upgrade';