feat: add first-interaction workflow for new contributors

[HosurSharanamma]

Summary

Adds a first-interaction.yml workflow that automatically posts a
welcome comment when someone opens their first issue or pull request
in the repository.

Motivation

Identified as a gap in issue #38 (CI parity analysis: opensovd-core
vs cicd-workflows). The opensovd-core repository already has this
workflow; this change brings cicd-workflows to parity.

Changes

• Added .github/workflows/first-interaction.yml using
  actions/first-interaction@v1
• Posts a welcome message on first issues reminding contributors to
  follow the contribution guidelines
• Posts a welcome message on first PRs reminding contributors about
  CI checks and the Eclipse DCO sign-off requirement

Testing

• Ran uv run https://raw.githubusercontent.com/eclipse-opensovd/cicd-workflows/main/run_checks.py locally — all checks passed
• Workflow syntax validated by check yaml and yamlfmt hooks

Relates to #38

[alexmohr]

Thank for your pull request :)

[alexmohr]

Awesome, thank you!

[lh-sag]

Please use 2026.

The trailing (see CONTRIBUTORS) is not common, I have not seen it in SCORE either. @alexmohr what was the intend of this remark and file. Could we simply remove it, at least he appearance in the comment.

[alexmohr]

Right now it is necessary to keep (see CONTRIBUTORS) otherwise the pipeline complains that the copyright header does not match. Year can be adjusted.
I'm not sure why we're using the copyright header with CONTRIBUTORS iirc @floroks was deeper involved in the discussion.

[alexmohr]

I'll clarify with the compliance people if this is necessary for some legal reasons, I'll report back

[alexmohr]

So feedback from our MBTI compliance people is pretty much what @lh-sag suggested :)

We can drop the (see Contributors) but keeping the block about notice etc (which no one discussed to remove here, just mentioning it for clarity) should be kept, because an Apache 2.0 licensed software must be shipped with a notice file if one is contained and mentioning it in the copyright makes it harder to miss the notice file (in theory at least).

Imho would make sense to do this in a follow up though.

[alexmohr]

#56 <-- follow up to fix this, as this is out of scope here.

[lh-sag]

Is there a way to point to the repositories CONTRIBUTING.md file?

Usually the projects have some specifics.

[alexmohr]

do they? In CDA we're missing the file entirely, but that could be an oversight on our end too 🙈

[lh-sag]

Maybe we can make the url overwritable then. If not specified pick the generic one as a fallback.

At least to me it would be odd getting such comment pointing to opensovd but I want the contribution guide from opensovd-cda/-core

[alexmohr]

probably would be best if each project just ships the file, if it's a carbon copy so be it, but it's also easier for newcomers to find it then. I'll make sure to fix this on cda side.

[HosurSharanamma]

Addressed all feedback:

Fixed copyright year from 2025 → 2026
Fixed workflow name from CI Checks → First Interaction (was conflicting with checks.yml)
Pinned runner from ubuntu-latest → ubuntu-24.04
@lh-sag @alexmohr for your review

[lh-sag]

Suggested change

	Please make sure you've reviewed our [contribution guidelines](https://github.com/eclipse-opensovd/opensovd/blob/main/CONTRIBUTING.md)
	Please make sure you've reviewed our [contribution guidelines](https://github.com/{{ github.repository_owner }}/${{ github.event.repository.name }}/blob/main/CONTRIBUTING.md)

@alexmohr would this work for you? Given that you add this file to cda.

@HosurSharanamma I am not sure whether this works. So feel free to experiment.

[alexmohr]

If that works that would be awesome.