chore: reduce proxy_cache max_size to 1m (single ~30KB JS file)

Author: mroderick

config/nginx.conf.erb

@@ -10,7 +10,7 @@ http {
   server_tokens off;
 
   # Proxy cache using /dev/shm (tmpfs, survives dyno restarts)
-  proxy_cache_path /dev/shm/jscache levels=1:2 keys_zone=jscache:1m inactive=30d use_temp_path=off max_size=10m;
+  proxy_cache_path /dev/shm/jscache levels=1:2 keys_zone=jscache:1m inactive=30d use_temp_path=off max_size=1m;
 
   # Security headers (set at http level to apply to all responses)
   add_header X-Frame-Options "SAMEORIGIN" always;