fix: use env to force API_SERVER_ENABLED=false in multi-gateway launcher

Shell prefix didn't work with nohup+gosu chain - Docker compose
env var API_SERVER_ENABLED=true leaked through. Using 'env'
command guarantees the override is in the child process env.

run-multi-gateways.sh

@@ -25,8 +25,7 @@ for profile in "${PROFILES[@]}"; do
   [ -z "${profile}" ] && continue
 
   echo "Starting gateway for profile: ${profile}"
-  API_SERVER_ENABLED=false \
-    nohup gosu hermes "$HERMES_BIN" --profile "${profile}" gateway run \
+  nohup env API_SERVER_ENABLED=false gosu hermes "$HERMES_BIN" --profile "${profile}" gateway run \
       >> "/opt/data/logs/gateway-${profile}.log" 2>&1 &
 done