Release workflow now pushes to both ghcr.io and Docker Hub on tag.
Adds shields.io Docker Pulls badge to README for social proof.
Requires DOCKERHUB_USERNAME and DOCKERHUB_TOKEN repo secrets.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Builds and pushes certctl-server and certctl-agent images to ghcr.io
when a version tag (v*) is pushed. Also creates a GitHub Release with
auto-generated release notes and Docker pull instructions.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>