Reuse runner-cached Docker base image

.gitea/workflows/build-runner-image.yml

@@ -55,8 +55,10 @@ jobs:
             --username "$REGISTRY_USERNAME" \
             --password-stdin
 
-          docker build \
-            --pull \
+          # The runner force-pulls this job's node:20-bookworm image before the
+          # job starts. Reuse that fresh host-cached image so BuildKit does not
+          # make a second anonymous Docker Hub token request.
+          DOCKER_BUILDKIT=0 docker build \
             --label "org.opencontainers.image.revision=$revision" \
             --label "org.opencontainers.image.source=https://mahgit.ir/MeghdadFadaee/daily-blackout-check" \
             --tag "$candidate" \