Add CI rollout baseline

[ohmyfelix]

What changed

• Added a Test job to build and smoke-test the Hashicorp image with non-interactive version checks.
• Kept the reusable Build job and added a master-only Docs job for Docker Hub description updates.
• Added Makefile run/test baseline targets and normalized README badges to the Dockette style.

Why

• Aligns dockette/hashicorp with the Dockette CI rollout baseline while keeping Docker Hub publishing and support links consistent.