Decide maintenance or replacement path for the global replication action

## Context

The global replicator relies on [`derberg/manage-files-in-multiple-repositories`](https://github.com/derberg/manage-files-in-multiple-repositories) across all replication jobs.

The workflow currently pins commit `beecbe897cf5ed7f3de5a791a3f2d70102fe7c25`, published in April 2023. The upstream repository has not received code updates since February 2025 and still declares an obsolete Node.js runtime.

Replication remains functional, but every job now warns that GitHub is forcing the action onto Node.js 24. This creates a future reliability and maintenance risk.

## Possible paths

1. **Contact the upstream author**

Ask @derberg whether the action is still maintained, whether Node.js 24 support is planned, and whether contributions or additional maintainers would be accepted.

2. **Maintain a Microcks fork**

Fork the action, update its runtime and dependencies, add tests, rebuild the distributed code, and preserve the inputs and behavior required by our global replicator.

[`Vendic/copy-files-to-other-repositories`](https://github.com/Vendic/copy-files-to-other-repositories/tree/feature/github-api) provides useful prior work for using the GitHub API instead of cloning every repository. However, that branch still uses Node.js 20 and should be treated as reference material rather than a ready replacement.

3. **Adopt another maintained solution**

Evaluate alternative actions or implement a dedicated GitHub API workflow. This would require more work to reproduce and validate the current exclusions, file copying/removal, branch creation, PR aggregation, fork/private filtering, and workflow-file permissions.

## Decision needed

- Should we contact upstream first and time-box the response?
- If upstream maintenance is unavailable, should Microcks maintain a compatible fork or evaluate a replacement?
- Which current behaviors must be preserved before migration?

No implementation PR should be opened until the preferred maintenance path is agreed.