Harden admin ops: integrations UI, uploads, pick/analytics polish.

Move PayU and carrier credentials into Settings, raise nginx upload limits, fix analytics Query translation, and improve orders pick/channel UX plus missing i18n.

Co-authored-by: Cursor <cursoragent@cursor.com>

docker/nginx-spa.conf

@@ -4,6 +4,11 @@ server {
   root /usr/share/nginx/html;
   index index.html;
 
+  # Product image uploads are up to 10 MB (API RequestSizeLimit).
+  # Nginx default is 1m and returns 413 for larger bodies.
+  client_max_body_size 12m;
+  client_body_timeout 120s;
+
   # Browser calls same-origin /api and /uploads; proxy to API container.
   location /api/ {
     proxy_pass http://api:8080/api/;
@@ -12,6 +17,10 @@ server {
     proxy_set_header X-Real-IP $remote_addr;
     proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
     proxy_set_header X-Forwarded-Proto $scheme;
+    proxy_request_buffering on;
+    proxy_connect_timeout 60s;
+    proxy_send_timeout 120s;
+    proxy_read_timeout 120s;
   }
 
   location /uploads/ {