Fix CI failure by making Docker push conditional on ENABLE_DOCKER_PUSH variable

[Copilot]

CI failing on docker-build-push job due to missing AZURE_CREDENTIALS secret. All Python tests pass but the workflow reports failure.

Changes

• Add vars.ENABLE_DOCKER_PUSH == 'true' condition to docker-build-push job
• Job now skips gracefully when Azure credentials aren't configured

if: github.event_name == 'push' && (github.ref == 'refs/heads/main' || startsWith(github.ref, 'refs/tags/')) && vars.ENABLE_DOCKER_PUSH == 'true'

To enable Docker builds

1. Set AZURE_CREDENTIALS secret
2. Create repository variable ENABLE_DOCKER_PUSH=true

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Investigat CI Failure</issue_title>
<issue_description>https://github.com/ianlintner/python_dsa/actions/runs/19809403873/job/56748830732</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Investigat CI Failure #15

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.