[Feature]: Add container image build and release workflow with semantic versioning

[mrhillsman]

Problem Statement

There is no automated build or release pipeline for the container image. The deployment manifest (deploy/deployment.yaml:32) and documentation (README.md:193, 229) reference quay.io/opdev/virtwork:latest with no versioned tags available. This creates several problems:

• No way to pin deployments to a known-good release
• No traceability from a running container back to a specific commit or version
• Library updates and future feature work will produce new builds with no versioning to distinguish them
• Rolling back to a previous version requires rebuilding from source

Proposed Solution

• GitHub Actions workflow that builds and pushes the container image on tagged releases
• Semantic version tags on images (e.g., quay.io/opdev/virtwork:v0.1.0)
• :latest tag automatically points to the most recent versioned build
• Image digest published in release notes for pinned deployments

Alternatives Considered

Not provided

Area

Other

Additional Context

Severity: Medium

[mrhillsman]

Resolved-by #35