Use runtime base to break gateway build cycle

.gitea/workflows/gateway-build.yml

@@ -7,7 +7,7 @@ on:
 
 env:
   DEPLOY_PATH: /opt/vpn-proxy
-  BASE_IMAGE: mirror.gcr.io/library/debian:bookworm-slim
+  BASE_IMAGE: vpn-proxy-runtime-base:bookworm-slim
   SINGBOX_VERSION: 1.12.13
 
 jobs:
@@ -39,6 +39,11 @@ jobs:
           echo "Base image: ${{ env.BASE_IMAGE }}"
           echo "Docker context: $(docker context show 2>/dev/null || true)"
           docker info 2>/dev/null | sed -n '/HTTP Proxy:/p;/HTTPS Proxy:/p;/Name:/p'
+          docker image inspect "${{ env.BASE_IMAGE }}" >/dev/null || {
+            echo "Runtime base image ${{ env.BASE_IMAGE }} is missing on lxc-107."
+            echo "Seed it once on 107 with: ./scripts/build-runtime-base.sh"
+            exit 1
+          }
 
           echo "${{ secrets.REGISTRY_TOKEN }}" | docker login "$REGISTRY_HOST" -u "${{ gitea.actor }}" --password-stdin
           DOCKER_BUILDKIT=1 docker build \
@@ -46,6 +51,8 @@ jobs:
             --pull=false \
             --build-arg BASE_IMAGE="${{ env.BASE_IMAGE }}" \
             --build-arg SINGBOX_VERSION="${{ env.SINGBOX_VERSION }}" \
+            --build-arg INSTALL_RUNTIME_DEPS=false \
+            --build-arg INSTALL_SINGBOX=false \
             -t "${IMAGE}:latest" \
             -t "${IMAGE}:${{ gitea.sha }}" \
             .