WorkflowTrim: Automated Detection, Repair and Savings Measurement of Resource-Waste Smells in GitHub Actions CI/CD Workflows

Repair fixes found in the RQ3 manual review (repair v0.9). The detector rules are unchanged (v0.4).

• S3: the cache uses the lock file in the directory where the install runs (working-directory, defaults.run.working-directory, cd). It is skipped when that directory is an expression or a variable, when a Gradle action already caches, and when setup-node has package-manager-cache: false.
• S8: a retention-days value set by the developers is kept; retention-days is added only when it is missing.
• New pr_study.py prepares repair pull requests for the developer study. It does not send anything.

The paper's results use v1.0 (doi:10.5281/zenodo.23417010). 73 tests pass.