chore(ci): add pull request previews

[emersion]

@mxmehl: would it be possible to add a new SSH key for NGE? I don't think we have a domain name for NGE yet though…

[mxmehl]

SSH key added. Please fix the preview subdir before running the next workflow.

[emersion]

Many thanks!

It seems like we're failing SSH authentication, do you think it's something you can fix on your side @mxmehl?

drone-scp version: 1.8.0
tar all files into /tmp/OsUYtEwtuH.tar.gz
remote server os type is unix
scp file to server.
2026/03/23 12:47:28 error copy file to dest: uberspace1.openrailassociation.org, error message: ssh: handshake failed: ssh: unable to authenticate, attempted methods [none publickey], no supported methods remain
drone-scp error:  error copy file to dest: uberspace1.openrailassociation.org, error message: ssh: handshake failed: ssh: unable to authenticate, attempted methods [none publickey], no supported methods remain

[mxmehl]

Oh sorry, that was my fault. SSH key is now working, @emersion.

But the deployment does not work. As far as I can see, the workflow doesn't have the necessary permissions:

permissions:
  contents: read
  # pull-requests: write # for sticky_comment_enabled, which you don't use
  deployments: write # for gh_deployment

[emersion]

Aha, yes, seems like we've been investigating in parallel :P

I've kept packages: write because we'll want to restore NPM package publishing in the near future, and I don't think contents: read is actually required here. Let's see how this goes!

[emersion]

Perfect, this now works as expected!

I've added a small additional commit to make it so NGE can be deployed in a subdir (see commit description for more details).

[louisgreiner]

This works so great, awesome!

[aiAdrian]

I don't understand what this PR / change will do -> please give more information (call?)

[mxmehl]

Fine from the technical side for me.

I am open to support you with hosting the prod instance on an OpenRail webserver as well, but that'd probably best handled in a separate PR.