Configure staging DNS and enable staging deploy

[Hqzdev]

Problem

Staging is not reachable at https://staging.metrixplatform.com.

Evidence

• curl -I https://staging.metrixplatform.com fails with Could not resolve host.
• Google DNS returns NXDOMAIN (Status: 3) for staging.metrixplatform.com A records.
• Production root https://metrixplatform.com resolves and returns 200 OK, so this is isolated to staging DNS.
• Latest CD run is green: https://github.com/Hqzdev/Metrix/actions/runs/27086713241
• In that run all Docker images built and pushed, but Deploy to staging and Smoke test staging were skipped.
• The deploy configuration job reports missing DEPLOY_PATH, SSH_HOST_STAGING, SSH_KNOWN_HOSTS, SSH_PRIVATE_KEY, and SSH_USER.

Related

• Configure SSH deploy secrets for CD environments #41 tracks missing SSH deploy secrets for CD environments. This issue tracks the staging-specific DNS/deploy readiness problem.

Acceptance criteria

• DNS A or CNAME record exists for staging.metrixplatform.com.
• GitHub Actions staging environment has the required SSH deploy settings.
• Next CD run executes Deploy to staging instead of skipping it.
• Staging smoke test passes against the configured staging URL.
• Root cause is documented in this issue.

[Hqzdev]

Staging deploy is being removed from the CD route instead of being configured. See #43.