Add a dashboard to visualise the Job queue and explore logs

[f-f]

Fix #742 - we add a Halogen dashboard to easily access the Job Queue and see the logs for each job.

The dashboard is deployed on GitHub Pages. I thought we should have a preview for each PR that changes the dashboard as well, so I added this, which is unfortunately not compatible with the default publish action, so I used this one instead, which is compatible.

A notable change is that I had to split the SSH module, so that we could use Registry.Operation in the frontend modules.

[github-actions]

PR Preview Action v1.8.1
🚀 View preview at https://purescript.github.io/registry-dev/pr-preview/pr-761/
Built to branch gh-pages at 2026-03-30 21:37 UTC. Preview will be ready when the GitHub Pages deployment is complete.

[thomashoneyman]

If we expect agents to be working on the dashboard is there anything specific you think should be added in a AGENTS.md (and symlinked CLAUDE.md) in the dashboard directory so that agents working there pick it up? Anything you noticed you needed to correct regarding Halogen, library choices, style, etc.?

[thomashoneyman]

A notable change is that I had to split the SSH module, so that we could use Registry.Operation in the frontend modules.

Is this outdated? I didn't see changes to the SSH module in the commits here.

[thomashoneyman]

Approving with non-blocking comments 🙏

[f-f]

Anything you noticed you needed to correct regarding Halogen, library choices, style, etc.?

Actually nothing at all, the thing is much better at Halogen than I ever was 🙂

Is this outdated? I didn't see changes to the SSH module in the commits here.

No changes in behaviour, we just extract a part of Registry.SSH into Registry.SSH.Signature so the Registry.Operation can import just that and the frontend does not need to have any node dependencies.