Container maintenance

[GernotMaier]

Maintenance points:

• updates base images from ALMA Linux 9.7 to 9.8
• updates base image python version from 3.12 to 3.14
• closes The "almalinux" image runs with "root" as the default user. #2349

[Copilot]

Pull request overview

This PR addresses issue #2349 by updating the AlmaLinux-based container images to run as a non-root default user (simtools) instead of root, aligning the container runtime posture with common security expectations.

Changes:

• Add configurable container user/UID/GID build args and switch runtime to USER simtools (with HOME set accordingly).
• Ensure /workdir and the user home are owned appropriately for non-root execution.
• Add a changelog fragment documenting the container maintenance change.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
docs/changes/2351.maintenance.md	Changelog entry for switching containers away from root.
docker/Dockerfile-simtools-prod	Create non-root user and set it as default user for the production simtools container.
docker/Dockerfile-simtools-dev	Create non-root user and set it as default user for the development simtools container.
docker/Dockerfile-simtel_array	Create non-root user and set it as default user for the sim_telarray runtime container.
docker/Dockerfile-corsika7	Create non-root user and set it as default user for the CORSIKA7 runtime container.

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[ctao-sonarqube]

Quality Gate passed

Issues
0 New issues
0 Fixed issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarQube