ci(HH-609): make cache export best-effort

Co-authored-by: multica-agent <github@multica.ai>

.github/workflows/docker.yml

@@ -82,6 +82,6 @@ jobs:
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}
           cache-from: type=gha
-          cache-to: type=gha,mode=max
+          cache-to: type=gha,mode=max,ignore-error=true
           provenance: mode=max
           sbom: true

tests/workflow-contract.sh

@@ -13,6 +13,7 @@ grep -F 'packages: write' "$workflow" >/dev/null
 grep -F 'ghcr.io/${{ github.repository }}' "$workflow" >/dev/null
 grep -F 'platforms: linux/amd64' "$workflow" >/dev/null
 grep -F 'needs: test' "$workflow" >/dev/null
+grep -F 'cache-to: type=gha,mode=max,ignore-error=true' "$workflow" >/dev/null
 # Match the GitHub expression literally.
 # shellcheck disable=SC2016
 grep -F 'push: ${{ github.event_name != '\''pull_request'\'' }}' "$workflow" >/dev/null