fix(build): skip empty gateway value in network config

When var_gateway is set to an empty string, the resulting gw= token
in the comma-separated network string causes pct create to fail with
a 'missing key in comma-separated list property' error.

Closes #13421

ct/koillection.sh

@@ -48,9 +48,7 @@ function update_script() {
     
     # Ensure APP_RUNTIME is in .env.local for CLI commands (upgrades from older versions)
     if ! grep -q "APP_RUNTIME" /opt/koillection/.env.local 2>/dev/null; then
-      # Ensure file ends with newline before appending to avoid concatenation
-      [[ -s /opt/koillection/.env.local && -n "$(tail -c 1 /opt/koillection/.env.local)" ]] && echo "" >>/opt/koillection/.env.local
-      echo 'APP_RUNTIME="Symfony\Component\Runtime\SymfonyRuntime"' >>/opt/koillection/.env.local
+      echo 'APP_RUNTIME="Symfony\Component\Runtime\SymfonyRuntime"' >> /opt/koillection/.env.local
     fi
     
     export COMPOSER_ALLOW_SUPERUSER=1

misc/build.func

@@ -3530,6 +3530,7 @@ build_container() {
   # Gateway
   if [[ -n "$GATE" ]]; then
     case "$GATE" in
+    ,gw=) ;;
     ,gw=*) NET_STRING+="$GATE" ;;
     *) NET_STRING+=",gw=$GATE" ;;
     esac