fix(nginx): drop duplicate application/x-rpm mime declaration

The mapping is already provided by /etc/nginx/mime.types on Fedora's
nginx package, so redeclaring it produced a duplicate-extension warning
on every `nginx -t`.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

asset/nginx/rpm.lair.cafe.conf

@@ -11,9 +11,6 @@ server {
     root /var/www/rpm;
 
     include /etc/nginx/mime.types;
-    types {
-        application/x-rpm rpm;
-    }
     default_type application/octet-stream;
 
     location /assets/ {