SONARRUBY-136 Set up orchestrator cache

[tomasz-tylenda-sonarsource]

• Add orchestrator cache action
• Use the new cache action in the QA job of the build workflow
• Add a cleanup-cache workflow for S3 cache inspection and manual cleanup

Tested: Checked the logs of https://github.com/SonarSource/sonar-ruby/actions/runs/24499072420/job/71601394007 (second run on the PR branch) and verified that sonarqube-enterprise-lw-2026.2.1.121354.zip was found in the cache.

🤖 Generated with Claude Code

[sonar-review-alpha]

Summary

This PR implements caching for the SonarQube orchestrator (downloaded binary) to speed up QA test runs. It introduces a reusable composite action that caches the orchestrator directory with a year-week cache key (auto-rotates weekly), and integrates it into the build workflow's QA job. A separate cleanup-cache workflow enables S3 cache inspection and manual deletion, with dry-run enabled by default for safety.

Tested on the PR's second workflow run with a real SonarQube build, confirming the orchestrator zip was successfully cached and retrieved.

What reviewers should know

Start here: Review the new orchestrator-cache action first (.github/actions/orchestrator-cache/action.yml) — it's the core implementation. Then check the integration point in build.yml where the action is called in the QA job.

Key design decisions:

• Cache key format (orchestrator-<version>-<year-week>-<run-id>) ensures weekly rotation and per-run uniqueness
• Caching is disabled for sq-version: 'DEV' to avoid stale dev artifacts
• The cleanup workflow uses workflow_dispatch (manual trigger) rather than scheduled, giving ops control over cache cleanup timing

Worth noting: The action sets environment variables (ORCHESTRATOR_CACHE_KEY and ORCHESTRATOR_HOME) that downstream steps can use. The mkdir -p and ls -lRh at the end of the action are useful for debugging and visibility into cache state across runs.

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[hashicorp-vault-sonar-prod]

SONARRUBY-136

[sonar-review-alpha]

LGTM! ✅

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[sonarqube-next]

Quality Gate passed for 'Ruby'

Issues
0 New issues
0 Fixed issues
0 Accepted issues

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

See analysis details on SonarQube

[alban-auzeill]

Perhaps we don't need github-ubuntu-latest-s (4 CPU, 16GB) and could use sonar-xs-public (1 CPU, 4GB) here. WDYT?