Remove all continue-on-error usages from CI workflows:
- deploy.yml: replace continue-on-error on SSH deploy steps with
if: secrets.SSH_PRIVATE_KEY != '' so steps are skipped (not failed)
when the secret is absent
- windows-nightly.yml: remove continue-on-error from job and steps
(job is already disabled via if: false)
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>