fix build workflow, docker improvements

[dgunzy]

Signed-off-by: Daniel Guns danbguns@gmail.com

• ## Summary

Fixed the Docker release build and added earlier CI coverage so the same issue is caught on PRs.

Changes

• Removed the invalid libapache2-mod-proxy-wstunel package from Dockerfile.
• Added python-is-python3 because Debian trixie provides python3, while Poetry expects python.
• Added /usr/local/apache2/bin to the image PATH so httpd is discoverable at runtime.
• Made Apache discovery portable in forevd/apache/__init__.py instead of hardcoding a Homebrew path.
• Added .dockerignore to keep Docker build contexts small and clean.
• Added a PR Docker build job using docker/build-push-action@v7.
• Updated GitHub Actions to current major versions to avoid Node 20 deprecation failures on release.

Verification

• poetry run pytest
• poetry run black --check .
• poetry run pylint forevd
• poetry run pycodestyle --config .pycodestyle forevd
• poetry build
• docker build --no-cache -t forevd:local-test .
• Container smoke tests with httpd -t, including OIDC module loading

closes #22

[bradpenney]

My name is Brad and I approve this pull request. 👍🏼