fix(release): harden SDK registry probes

[ZhiXiao-Lin]

Summary

• write registry responses and headers to runner temporary files
• parse the final HTTP status from response headers
• preserve strict 200/404 validation and idempotent SDK publishing

Validation

• git diff --check
• exercised both probes against npm and PyPI (404 as expected for 3.1.0)
• parsed .github/workflows/publish-sdk.yml as YAML

This avoids the repeatable curl exit 23 seen in SDK publish run 30023154428.