fix(ui): strip ui prefix from static navigation payloads

ui/nginx.conf

@@ -91,6 +91,9 @@ http {
     # /ui/<page>.txt would otherwise be rewritten to HTML and break RSC
     # for nested routes. A genuinely missing payload must 404 (the
     # router degrades to a hard navigation); never fall back to HTML.
+    location ~ ^/ui/(.+\.txt)$ {
+      try_files /$1 =404;
+    }
     location ~ \.txt$ {
       try_files $uri =404;
     }