fix: add pull:true to security rebuild to fetch fresh base images

Without pull:true, the weekly security rebuild may use stale base
images cached on GitHub runners, missing security patches like
c-ares 1.34.6-r0 (CVE-2025-62408).

.github/workflows/security-weekly-rebuild.yml

@@ -71,6 +71,7 @@ jobs:
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}
           no-cache: ${{ github.event_name == 'schedule' || inputs.force_rebuild }}
+          pull: true  # Always pull fresh base images to get latest security patches
           build-args: |
             VERSION=security-scan
             BUILD_DATE=${{ fromJSON(steps.meta.outputs.json).labels['org.opencontainers.image.created'] }}