fix(ci): drop OCI labels from the pack build

pack build has no --label flag; the buildpacks image carries the lifecycle's metadata labels, as it
did under the Maven plugin.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

Author: FelixTJDietrich

.github/workflows/ci-build.yml

@@ -96,10 +96,5 @@ jobs:
       # renovate: datasource=docker depName=paketobuildpacks/ubuntu-noble-run-tiny
       run-image: "paketobuildpacks/ubuntu-noble-run-tiny@sha256:c32333227b6dfbc2a4a93b03ee6d3475cfe152468c7d396bf22f06099bb0ecc9"
       registry: "ghcr.io"
+      # Buildpacks images carry the lifecycle's own metadata labels; pack accepts no OCI labels.
       single-arch: ${{ github.event_name == 'pull_request' || github.event_name == 'merge_group' }}
-      labels: |
-        org.opencontainers.image.title=Hephaestus Application Server
-        org.opencontainers.image.description=Spring Boot server for Hephaestus
-        org.opencontainers.image.vendor=AET TUM
-        org.opencontainers.image.licenses=MIT
-        hephaestus.component=application-server

.github/workflows/reusable-docker-build.yml

@@ -203,13 +203,9 @@ jobs:
           [[ -n "$PROJECT_DESCRIPTOR" && -n "$RUN_IMAGE" ]]
           mapfile -t jars < <(find "$APPLICATION_DIRECTORY" -name 'hephaestus-application-*.jar')
           (( ${#jars[@]} == 1 ))
-          mapfile -t labels < <(jq -r '.labels | to_entries[] | "\(.key)=\(.value)"' <<< "$DOCKER_METADATA_OUTPUT_JSON")
-          label_args=()
-          for label in "${labels[@]}"; do label_args+=(--label "$label"); done
           PER_ARCH_TAG="$INPUT_REGISTRY/$INPUT_IMAGE_NAME:ci-$GITHUB_RUN_ID-$PLATFORM_PAIR"
           pack build "$PER_ARCH_TAG" --path "${jars[0]}" --descriptor "$PROJECT_DESCRIPTOR" \
-            --run-image "$RUN_IMAGE" --platform "$MATRIX_PLATFORM" --publish --trust-builder \
-            "${label_args[@]}"
+            --run-image "$RUN_IMAGE" --platform "$MATRIX_PLATFORM" --publish --trust-builder
           # Buildpacks may wrap one platform in an index; capture its manifest, not the wrapper.
           RAW=$(docker buildx imagetools inspect "$PER_ARCH_TAG" --format '{{json .Manifest}}')
           if echo "$RAW" | jq -e '.manifests' >/dev/null 2>&1; then