Robustness of CI

[GernotMaier]

A lot of CI runs are failing with network issues. This PR tries to increase the robustness.

CI Unit tests.

• clearly separate Sonar from the unit tests. This does not increase robustness, but allows to see easier that the issue is with sonar and not with the unit tests (e.g., in a draft PR, would ignore the message then).
• some sonar runs fail already when downloading the sonar binary (https://binaries.sonarsource.com/Distribution/sonar-scanner-cli/sonar-scanner-cli-8.1.0.6389-linux-x64.zip). Add a caching step for this binary.
• retry 3x sonar analysis for connection issues.
• allow sonar to fail if the PR is in draft status.

CI Integration Tests

• cache both simulation models and CORSIKA interaction tables
• first try to run the git clone of both repositories (as before). If this fails, fall back to the cached version.

[Copilot]

Pull request overview

This pull request aims to reduce CI flakiness caused by network issues by separating SonarQube from unit tests and introducing caching/fallback behavior for external resources (Sonar scanner binary, CORSIKA interaction tables, simulation models).

Changes:

• Split SonarQube analysis into a dedicated sonarqube job, using a cached Sonar scanner and retry logic, and allowing soft-fail on draft PRs.
• Upload/download a coverage artifact to feed SonarQube independently of the unit test job.
• Add cache restore/save + “clone-then-fallback-to-cache” logic for CORSIKA interaction tables and simulation models in integration tests.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.

File	Description
docs/changes/2239.maintenance.md	Adds a changelog fragment describing CI robustness improvements.
.github/workflows/CI-unittests.yml	Separates SonarQube into its own job and passes coverage via artifacts; adds scanner caching/retry logic.
.github/workflows/CI-integrationtests.yml	Adds caching and fallback behavior for GitLab-hosted interaction tables and simulation models to mitigate network failures.

[ctao-sonarqube]

Quality Gate passed

Issues
0 New issues
0 Fixed issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
No data about Duplication

See analysis details on SonarQube